**4. Issues of the presence of Ph chromosome or BCR-ABL gene in non-CML hematological malignancies or healthy individuals**

Ph chromosome, t(9;22)(q34.1;q11.2), was found in CML at 90–95% as mentioned above [41]. However, Ph chromosome has been found in other types of non-CML hematological malignancies.

Studies showed that acute myeloid leukemia (AML) about 3% of adult AML and 1% in childhood have Ph chromosome [42, 43]. Different proportions of Ph chromosome were found in patient with myelodysplasia syndrome (MDS) [44]. About 20% of adult ALL and 2–5% of children have Ph chromosome in acute lymphoblastic leukemia (ALL) [45–48]. The couple of T-ALL cases with positive Ph have been reported [49, 50]. The presence of Ph chromosome on a patient with lymphoma was detected by a study [51]. Positive Ph chromosome was reported from H929 multiple myeloma cell line [52]. Koshy group reported the presence of Ph chromosome from a case of pregnant women with unusual primary myelofibrosis [53].

Interestingly and surprisingly, BCR-ABL fusion gene was detected in healthy individuals (2/30) but without following up studies seen afterward [54]. Biernaux group studied the BCR-ABL gene of blood cells from healthy individuals and found the presence of BCR-ABL transcript (22 of 73) [55]. More evidence from a study of peripheral blood leukocytes conducted on 16 healthy individuals, and some cell lines as controls by Bose group and results showed the presence of BCR-ABL gene either p210 (27%) or p190 (69%) transcript in healthy individuals [56]. It is suggested that leukemia-associated genes in healthy individuals require the additional activations to be malignancy, although no satisfactory explanation on why BCR/ ABL fusion gene detected from some healthy individuals short- and long-term following up.
