**2.3.3 Results of cellular infiltration in tumors of epithelial origin**

In most cases, infiltrates were located predominantly in the stroma at the periphery of the tumor, and, in rare cases, occurred in the glandular alveoli. Inflammatory infiltrates consisted of lymphocytes, neutrophils and macrophages. The intensity of cellular infiltration was assessed on a four-level scale:: -/+; +; ++; +++. Statistical analysis indicates no correlation between the age of the dog and the intensity of cellular infiltration in the tumor. It is worth noting that, in bitches between the ages of 8 to 12 years, most tumors exhibited the intensity of infiltration at the first (+) level , which constituted 50% of tumors in this age group. A significant relationship was found between the intensity of cellular infiltration and the type of tumor. In 50% of solid cancers, there was no cellular infiltration. Only 33% of these tumors exhibited the presence of cellular infiltration at the first level (+), and 16.7% on the second level (++). Among the complex cancers, the largest group consisted of those, in which cellular infiltration was found at the first (+) and the second (++) level. The highest average intensity of cellular infiltration was found in complex carcinomas, followed by simple carcinomas, adenomas and solid carcinomas. Specific differences were seen between adenomas and complex carcinomas (P=0.007) and between solid carcinomas and complex carcinomas (P=0.005). While examining the relationship between intensity of cellular infiltration and histological grade of malignancy, no significant differences were revealed. But it may be noted that among tumors of all histological grades of malignancy, the largest group consisted of cancers with the first level of cellular infiltration. While analyzing the average intensity of cellular infiltration in tumors with various histological grades of malignancy no significant differences were found between groups with the exception of the tumors in the 3rd grade, where a significant difference was observed (P=0.023).

Prospective Study of Tumor Markers as Prognostic Factors

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 207

receptors reveals that the level of expression increases with the histological grade of malignancy. It was also found that most tumors expressing estrogen receptors came from dogs younger than 8 years. A positive correlation was found between mitotic index and expression of estrogen receptors in specific types of cancer and statistically significant

Fig. 7. Average number of cells showing p53 expression depending on the tumor grade.

Fig. 8. Adenocarcinoma complex, expression of ER, immunohistochemical method. (40x)

differences between tumor characteristics were demonstrated (P=0.042).

### **2.3.4 Results of p53 expression in neoplasms of mammary gland**

Expression of p53 protein was observed in the nuclei of cancer cells (Fig.6). Positive reaction of p53 protein was observed in 70 (52.6%) of all tumors. Expression of p53 protein was found in 4 adenomas. The largest group of tumors positive for p53 protein were complex and simple cancers. Solid cancers belonged to a group, which rarely exhibited a positive reaction for nuclear p53. Analysis of the average number of cells with a positive reaction for p53 showed its highest expression in the case of complex cancers, as well as in 1st and 2nd grade tumors (Fig.7). The lowest level of expression of p53 protein was found in adenomas.

Fig. 6. Adenocarcinoma simplex, expression of p53, immunohistochemical method. (40x)

No statistically significant differences were shown between the examined groups. Comparing the ages of bitches, the highest average number of cells expressing p53 protein was found in tumors excised from younger dogs. However, there were no statistically significant differences among the age groups.

#### **2.3.5 Results of estrogen receptor expression in neoplasms of mammary gland**

Estrogen receptor expression was detected in the nuclei of tumor cells, but it was also seen in the cytoplasm. Cytoplasmic reaction was considered to be nonspecific. Among all tumors of epithelial origin, expression of estrogen receptors was found in 54 (40.6%) , and no reaction was noted in 79 (59.4%). Expression of estrogen receptors was most commonly found in complex cancers (43.9%) (Fig.8) , followed by simple cancers (42.6%) (Fig.9, Fig.10) and adenomas (28.6%), while solid cancers rarely expressed them (16.7%). The highest expression of estrogen receptors was found in simple carcinomas as well as in 3rd grade tumors, but no statistically significant differences were found between study groups (Fig. 11). Analysis of the average number of cells showing positive expression of estrogen

Expression of p53 protein was observed in the nuclei of cancer cells (Fig.6). Positive reaction of p53 protein was observed in 70 (52.6%) of all tumors. Expression of p53 protein was found in 4 adenomas. The largest group of tumors positive for p53 protein were complex and simple cancers. Solid cancers belonged to a group, which rarely exhibited a positive reaction for nuclear p53. Analysis of the average number of cells with a positive reaction for p53 showed its highest expression in the case of complex cancers, as well as in 1st and 2nd grade tumors (Fig.7). The lowest level of expression of p53 protein was found in adenomas.

Fig. 6. Adenocarcinoma simplex, expression of p53, immunohistochemical method. (40x)

**2.3.5 Results of estrogen receptor expression in neoplasms of mammary gland** 

significant differences among the age groups.

No statistically significant differences were shown between the examined groups. Comparing the ages of bitches, the highest average number of cells expressing p53 protein was found in tumors excised from younger dogs. However, there were no statistically

Estrogen receptor expression was detected in the nuclei of tumor cells, but it was also seen in the cytoplasm. Cytoplasmic reaction was considered to be nonspecific. Among all tumors of epithelial origin, expression of estrogen receptors was found in 54 (40.6%) , and no reaction was noted in 79 (59.4%). Expression of estrogen receptors was most commonly found in complex cancers (43.9%) (Fig.8) , followed by simple cancers (42.6%) (Fig.9, Fig.10) and adenomas (28.6%), while solid cancers rarely expressed them (16.7%). The highest expression of estrogen receptors was found in simple carcinomas as well as in 3rd grade tumors, but no statistically significant differences were found between study groups (Fig. 11). Analysis of the average number of cells showing positive expression of estrogen

**2.3.4 Results of p53 expression in neoplasms of mammary gland** 

receptors reveals that the level of expression increases with the histological grade of malignancy. It was also found that most tumors expressing estrogen receptors came from dogs younger than 8 years. A positive correlation was found between mitotic index and expression of estrogen receptors in specific types of cancer and statistically significant differences between tumor characteristics were demonstrated (P=0.042).

Fig. 7. Average number of cells showing p53 expression depending on the tumor grade.

Fig. 8. Adenocarcinoma complex, expression of ER, immunohistochemical method. (40x)

Prospective Study of Tumor Markers as Prognostic Factors

of estrogen receptors was found in simple cancer types.

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 209

Fig. 11. An average number of cells showing ER expression depending on the tumor grade

Expression of cyclooxygenase – 2 was observed in the neoplastic cell cytoplasm. It was confirmed in 13 of 14 adenomas. Similar results were obtained in solid cancers (5 of 6) (Fig. 12). Positive COX–2 reaction was found in 36.9% of simple carcinomas (Fig.13). Of all tumors, which exhibited a positive response (122), complex tumors demonstrated the highest percentage (48.4%). Statistical analysis, however, failed to demonstrate any significant differences regarding the COX–2 expression between the individual types of carcinoma (P = 0.978). According to the analysis of histological malignancy grades, the highest expression was found in 3rd grade cancers and statistical significance was confirmed for the individual histological malignancy grades (P = 0.047) (Fig. 14, Fig. 15). Furthermore, higher COX-2 expression level was demonstrated in carcinomas with higher mitotic index; statistical analysis demonstrated highly significant differences between neoplasms with high versus low mitotic index (P = 0.009) (Fig.16). The investigation into the relationship between expression of Ki-67 nuclear antigen and the COX–2 expression level did not reveal statistical significance (P = 0.614) (Fig. 17). Analysis of the relationship between the p53 protein expression and COX–2 expression level demonstrated a statistically significant correlation between these features (P = 0.034) (Fig. 18). An average number of cells expressing p53 protein was higher in carcinomas with higher COX–2 expression. In addition, experiments explored the relationship between Hsp70 protein and cyclooxygenase – 2 expression levels. The study proved a statistically high correlation between the investigated neoplastic characteristics (P = 0.006). The lowest Hsp70 protein expression was found in carcinomas exhibiting second degree COX–2 expression (Fig. 19). Analysis of the relationship between representative neoplastic features demonstrated statistically significant, positive correlations between COX–2 expression, mitotic index (P = 0.009) and p53 protein expression (P = 0.003); on the other hand, no correlation was found with regard to the Ki-67 nuclear antigen expression (P = 0.686). There was no correlation between the estrogen receptor expression and the above mentioned parameters. The highest expression

**2.3.6 Results of cyclooxygenase-2 expression in neoplasms of mammary gland** 

Fig. 9. Adenocarcinoma simplex, expression of ER, immunohistochemical method. (100x)

Fig. 10. Adenocarcinoma simplex, expression of ER, immunohistochemical method. (100x)

Fig. 9. Adenocarcinoma simplex, expression of ER, immunohistochemical method. (100x)

Fig. 10. Adenocarcinoma simplex, expression of ER, immunohistochemical method. (100x)

Fig. 11. An average number of cells showing ER expression depending on the tumor grade

#### **2.3.6 Results of cyclooxygenase-2 expression in neoplasms of mammary gland**

Expression of cyclooxygenase – 2 was observed in the neoplastic cell cytoplasm. It was confirmed in 13 of 14 adenomas. Similar results were obtained in solid cancers (5 of 6) (Fig. 12). Positive COX–2 reaction was found in 36.9% of simple carcinomas (Fig.13). Of all tumors, which exhibited a positive response (122), complex tumors demonstrated the highest percentage (48.4%). Statistical analysis, however, failed to demonstrate any significant differences regarding the COX–2 expression between the individual types of carcinoma (P = 0.978). According to the analysis of histological malignancy grades, the highest expression was found in 3rd grade cancers and statistical significance was confirmed for the individual histological malignancy grades (P = 0.047) (Fig. 14, Fig. 15). Furthermore, higher COX-2 expression level was demonstrated in carcinomas with higher mitotic index; statistical analysis demonstrated highly significant differences between neoplasms with high versus low mitotic index (P = 0.009) (Fig.16). The investigation into the relationship between expression of Ki-67 nuclear antigen and the COX–2 expression level did not reveal statistical significance (P = 0.614) (Fig. 17). Analysis of the relationship between the p53 protein expression and COX–2 expression level demonstrated a statistically significant correlation between these features (P = 0.034) (Fig. 18). An average number of cells expressing p53 protein was higher in carcinomas with higher COX–2 expression. In addition, experiments explored the relationship between Hsp70 protein and cyclooxygenase – 2 expression levels. The study proved a statistically high correlation between the investigated neoplastic characteristics (P = 0.006). The lowest Hsp70 protein expression was found in carcinomas exhibiting second degree COX–2 expression (Fig. 19). Analysis of the relationship between representative neoplastic features demonstrated statistically significant, positive correlations between COX–2 expression, mitotic index (P = 0.009) and p53 protein expression (P = 0.003); on the other hand, no correlation was found with regard to the Ki-67 nuclear antigen expression (P = 0.686). There was no correlation between the estrogen receptor expression and the above mentioned parameters. The highest expression of estrogen receptors was found in simple cancer types.

Prospective Study of Tumor Markers as Prognostic Factors

grade.

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 211

Fig. 14. Average number of cells exhibiting COX-2 expression depending on the tumor

Fig. 15. Average level of COX-2 expression depending on tumor grade. Letters (a, b, c) above the columns show that the difference between means was statistically significant (P≤0,05).

Fig. 12. Carcinoma solidum, expression of COX–2, immunohistochemical method. (100x)

Fig. 13. Adenocarcinoma simplex, expression of COX–2, immunohistochemical method. (100x)

Fig. 12. Carcinoma solidum, expression of COX–2, immunohistochemical method. (100x)

Fig. 13. Adenocarcinoma simplex, expression of COX–2, immunohistochemical method.

(100x)

Fig. 14. Average number of cells exhibiting COX-2 expression depending on the tumor grade.

Fig. 15. Average level of COX-2 expression depending on tumor grade. Letters (a, b, c) above the columns show that the difference between means was statistically significant (P≤0,05).

Prospective Study of Tumor Markers as Prognostic Factors

means was statistically significant (P≤0.05).

means was statistically significant (P≤0.05).

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 213

Fig. 18. Average number of cells expressing p53, depending on the degree of expression of cyclooxygenase – 2. Letters (a, b) above the columns show that the difference between

Fig. 19. Average number of cells expressing Hsp70, depending on the degree of expression of cyclooxygenase – 2. Letters (a, b) above the columns show that the difference between

**2.3.7 Results of P-glycoprotein expression in neoplasms of the mammary gland** 

Expression of P-glycoprotein was identified in cytoplasm and cell membranes of neoplastic cells. Positive reaction was found in 76% of all neoplasms. Complex carcinomas were the biggest group among cancer types, which demonstrated positive reaction to P-gp. In terms

Fig. 16. Average value of mitotic index in tumors with different degrees of expression of cyclooxygenase – 2. Letters (a, b, c, d) above the columns show that the difference between means was statistically significant (P≤0.05).

Fig. 17. Average number of cells expressing Ki-67, depending on the degree of expression of cyclooxygenase – 2.

Fig. 16. Average value of mitotic index in tumors with different degrees of expression of cyclooxygenase – 2. Letters (a, b, c, d) above the columns show that the difference between

Fig. 17. Average number of cells expressing Ki-67, depending on the degree of expression of

means was statistically significant (P≤0.05).

cyclooxygenase – 2.

Fig. 18. Average number of cells expressing p53, depending on the degree of expression of cyclooxygenase – 2. Letters (a, b) above the columns show that the difference between means was statistically significant (P≤0.05).

Fig. 19. Average number of cells expressing Hsp70, depending on the degree of expression of cyclooxygenase – 2. Letters (a, b) above the columns show that the difference between means was statistically significant (P≤0.05).

#### **2.3.7 Results of P-glycoprotein expression in neoplasms of the mammary gland**

Expression of P-glycoprotein was identified in cytoplasm and cell membranes of neoplastic cells. Positive reaction was found in 76% of all neoplasms. Complex carcinomas were the biggest group among cancer types, which demonstrated positive reaction to P-gp. In terms

Prospective Study of Tumor Markers as Prognostic Factors

histological grade of malignancy, described by a low apoptotic index.

Fig. 21. Adenoma, expression of Hsp70, immunohistochemical method. (20x)

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 215

antigen Ki-67 expression. It was found that the expression of nuclear antigen Ki-67 was most pronounced in solid tumors, as was the expression of Hsp90. Also, in neoplasms of the highest grade, expression of nuclear antigen Ki-67 and protein Hsp90 was the highest. High expression of Hsp70 was found in tumors with grade 1 and 3 of cyclooxygenase-2 expression, whereas the lowest Hsp70 expression was observed in tumors with grade 2 of cyclooxygenase-2 expression. Statistical significance was found between the investigated features of neoplasms (P=0.009). Increased expression of cyclooxygenase-2 was observed in tumors with a low mean number of cells showing positive immunohistochemical reaction for protein Hsp90. The highest level of expression of this protein was confirmed in tumors with grade 1 of cyclooxygenase-2 expression (Fig. 27). Between the mean number of cells showing positive Hsp90 reaction and cyclooxygenase-2 expression, there was a statistical significance observed for grade 1 and 2 of cyclooxygenase-2 expression (P=0.039). Statistical analysis proved a correlation between Hsp70 and p53 protein expression in tumors of epithelial origin. High statistical significance was shown for investigated neoplastic features (P = 0.002). Taking into account the type of tumor, expression of both proteins was highest in complex carcinomas and tumors with the lowest histological grade. High expression levels of Hsp90 protein and Ki-67 nuclear antigen was shown in cases of solid carcinomas and in carcinomas exhibiting 3rd

of histological malignancy grade, the most numerous were cancers featuring the lowest grade of malignancy (Fig. 20). In female canines aged 9 through 12 years, cancers exhibiting a positive P-gp reaction constituted the most numerous group (63.2%); on the other hand, this cancer type barely appeared in the oldest group (10.5%). Analysis of the average P glycoprotein expression in different types of carcinomas did not reveal any significant differences. Correspondingly, evaluation of malignancy grade showed no statistical significance between examined features. Among different cancer types, the highest P-gp expression was demonstrated in solid carcinomas and cancers featuring the highest histological grade of malignancy. Positive correlation between investigated cancer features was found in the analysis of the relationship between cyclooxygenase-2 and P-gp expression, where P value was equal to 0.021.

Fig. 20. Average expression level of P–gp depending on the tumor grade.

#### **2.3.8 Results of heat shock protein expression in neoplasms of mammary gland**

Heat shock proteins were found in the cytoplasm and nuclei of cancer cells (Fig. 21, Fig. 22, Fig. 23, Fig. 24). The largest group of tumors exhibiting Hsp70 and Hsp90 expression included simple and complex cancers, whereas solid tumors were the least numerous group. Grade 1 and 2 cancers constituted the largest group expressing both Hsp70 and Hsp90 (Fig. 25, Fig. 26) . Immunohistochemical analysis showed high expression of Hsp90 in simple and complex cancers, but no statistically significant differences were found between investigated types of tumors (P=0.443). High expression of Hsp90 was confirmed in solid cancers and, in this particular group, significant differences were found between types of tumor (P=0.032). As far as grading was concerned, no statistically significant differences were found between the mean number of cells exhibiting Hsp70 and Hsp90 protein expression and malignancy grade. When comparing the expression of Hsp70 to the expression of Hsp90 in particular types of cancers, we found a highly significant statistical difference (P=0.005) between the expression of both proteins. Results of a study on the expression of heat shock proteins (Hsp70 and Hsp90) were compared to nuclear

of histological malignancy grade, the most numerous were cancers featuring the lowest grade of malignancy (Fig. 20). In female canines aged 9 through 12 years, cancers exhibiting a positive P-gp reaction constituted the most numerous group (63.2%); on the other hand, this cancer type barely appeared in the oldest group (10.5%). Analysis of the average P glycoprotein expression in different types of carcinomas did not reveal any significant differences. Correspondingly, evaluation of malignancy grade showed no statistical significance between examined features. Among different cancer types, the highest P-gp expression was demonstrated in solid carcinomas and cancers featuring the highest histological grade of malignancy. Positive correlation between investigated cancer features was found in the analysis of the relationship between cyclooxygenase-2 and P-gp

expression, where P value was equal to 0.021.

Fig. 20. Average expression level of P–gp depending on the tumor grade.

**2.3.8 Results of heat shock protein expression in neoplasms of mammary gland** 

Heat shock proteins were found in the cytoplasm and nuclei of cancer cells (Fig. 21, Fig. 22, Fig. 23, Fig. 24). The largest group of tumors exhibiting Hsp70 and Hsp90 expression included simple and complex cancers, whereas solid tumors were the least numerous group. Grade 1 and 2 cancers constituted the largest group expressing both Hsp70 and Hsp90 (Fig. 25, Fig. 26) . Immunohistochemical analysis showed high expression of Hsp90 in simple and complex cancers, but no statistically significant differences were found between investigated types of tumors (P=0.443). High expression of Hsp90 was confirmed in solid cancers and, in this particular group, significant differences were found between types of tumor (P=0.032). As far as grading was concerned, no statistically significant differences were found between the mean number of cells exhibiting Hsp70 and Hsp90 protein expression and malignancy grade. When comparing the expression of Hsp70 to the expression of Hsp90 in particular types of cancers, we found a highly significant statistical difference (P=0.005) between the expression of both proteins. Results of a study on the expression of heat shock proteins (Hsp70 and Hsp90) were compared to nuclear antigen Ki-67 expression. It was found that the expression of nuclear antigen Ki-67 was most pronounced in solid tumors, as was the expression of Hsp90. Also, in neoplasms of the highest grade, expression of nuclear antigen Ki-67 and protein Hsp90 was the highest. High expression of Hsp70 was found in tumors with grade 1 and 3 of cyclooxygenase-2 expression, whereas the lowest Hsp70 expression was observed in tumors with grade 2 of cyclooxygenase-2 expression. Statistical significance was found between the investigated features of neoplasms (P=0.009). Increased expression of cyclooxygenase-2 was observed in tumors with a low mean number of cells showing positive immunohistochemical reaction for protein Hsp90. The highest level of expression of this protein was confirmed in tumors with grade 1 of cyclooxygenase-2 expression (Fig. 27). Between the mean number of cells showing positive Hsp90 reaction and cyclooxygenase-2 expression, there was a statistical significance observed for grade 1 and 2 of cyclooxygenase-2 expression (P=0.039). Statistical analysis proved a correlation between Hsp70 and p53 protein expression in tumors of epithelial origin. High statistical significance was shown for investigated neoplastic features (P = 0.002). Taking into account the type of tumor, expression of both proteins was highest in complex carcinomas and tumors with the lowest histological grade. High expression levels of Hsp90 protein and Ki-67 nuclear antigen was shown in cases of solid carcinomas and in carcinomas exhibiting 3rd histological grade of malignancy, described by a low apoptotic index.

Fig. 21. Adenoma, expression of Hsp70, immunohistochemical method. (20x)

Prospective Study of Tumor Markers as Prognostic Factors

(10x)

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 217

Fig. 24. Adenocarcinoma complex, expression of Hsp90, immunohistochemical method.

Fig. 25. Average number of cells showing Hsp70 expression depending on the tumor grade.

Fig. 22. Adenocarcinoma simplex, expression of Hsp70, immunohistochemical method. (100x)

Fig. 23. Adenocarcinoma complex, expression of Hsp70, immunohistochemical method. (100x)

Fig. 22. Adenocarcinoma simplex, expression of Hsp70, immunohistochemical method. (100x)

Fig. 23. Adenocarcinoma complex, expression of Hsp70, immunohistochemical method.

(100x)

Fig. 24. Adenocarcinoma complex, expression of Hsp90, immunohistochemical method. (10x)

Fig. 25. Average number of cells showing Hsp70 expression depending on the tumor grade.

Prospective Study of Tumor Markers as Prognostic Factors

in the Histopathological Differential Diagnosis of Mammary Gland Neoplasms in Female Canines 219

Löhr (1997) found that 50% of the mammary gland tumors in female canines are malignant tumors (Löhr et al, 1997). Hellmén (1993) determined the incidence of malignant tumors to be 68% (Hellmén et al 1993). There are also studies showing, that about a half of tumors are benign (Bostock et al, 1992; Gilbertson et al, 1983). Moulton (1990) believes that benign tumors represent about 80% of cases and the majority of tumors studied are "benign mixed tumors" (65%) (Moulton, 1990). They are tumors in which, apart from epithelial and mesenchymal tissue, there is also cartilage and bone tissue. Their histopathological examination reveals no sign of malignancy. Nerurkar (1990) says that benign tumors represent about 27% of the mammary gland tumors in female dogs (Nerurkar et al, 1990). In our study, benign tumors of epithelial origin accounted for only 10.1% of all cases. The diversity of these results relates to the lack of uniform diagnostic criteria and lack of uniform classification of tumors of the mammary gland in dogs. In human medicine, age is a very important prognostic factor. Detection of breast cancer in women at a very young age and at the age over 60 is associated with worse prognosis (Host & Lund, 1986). In Philibert's (2003) studies there were no significant differences in survival of young and older dogs (Philibert et al, 2003). Hellmén (1993) presented completely different results (Hellmén et al, 1993). She found that age may be an important prognostic factor and showed that older bitches had a shorter survival time after surgery. Results obtained by Benjamin corresponded to that (1999) (Benjamin et al, 1999). Own results support the concept of age as an important prognostic factor, as there is very little information regarding survival or recurrence of malignancy in female dogs after surgery. Current study shows that the presence or absence of cellular inflammatory infiltrates may be a prognostic factor. Data on the incidence of cellular infiltration in mammary gland tumors in female dogs is also scarce. Gilbertson (1983) found that cell infiltration plays a role in the process of development of precancerous and invasive carcinomas (35%) (Gilbertson et al, 1983). In our study, the percentage of tumors with cellular infiltration was higher (88%). The highest intensity of cellular infiltration was observed in tumors with a high histological grade of malignancy. Skrzypczak (2004) (Skrzypczak, 2004) presented similar results in his study . Authors believe that presence of cellular infiltration plays a positive role in inhibiting tumor growth. Some studies have shown that presence of cellular infiltration is associated with good (Rilke et al, 1991) or poor (Parl & Dupont, 1982) prognosis and others, that it carries no prognostic value. In our study, no relationship was found between cellular infiltration and other tumor markers, consistent with the studies by Rodo (2007) (Rodo, 2007; Roses et al, 1982). It is worth noting the presence of necrosis in tumor foci, which may obscure the accuracy of the results. Necrosis in the tumor is the result of disparities between high proliferative activity and tumor vascularization. It may trigger cellular inflammatory reactions. We also analyzed the distribution of cellular infiltration. Our own results differ from the results of other authors, because infiltration was observed in the stroma, not scattered (Lee et al, 1996), and was more pronounced on the periphery of the tumor. The role of cellular infiltration within the tumor remains unclear and controversial. Estrogen receptors are recognized markers in the diagnosis of breast cancer in women. It is estimated that about 70-80% of breast cancers in women exhibit the expression of estrogen receptors. These tumors are characterized by slower growth, higher diversity, better prognosis with a suitable treatment regimen and correlate with the length of survival after

Fig. 26. Average number of cells showing Hsp90 expression depending on the tumor grade

Fig. 27. Average number of cells expressing Hsp90, depending on the degree of cyclooxygenase – 2 expression. Letters (a, b) above the columns show that the difference between means was statistically significant (P≤0.05).
