**8. Canine detection of cervical cancer**

Issues concerning CC detection make it necessary searching for alternatives that help to increase the early screening coverage with greater percentages of sensitivity and specificity in screening and diagnostic tests. The introduction of methods capable of detecting virtually invisible -a single molecule among a billion or trillions of compounds- changes in the cell through the analysis of cells "odor" have much in their favor in practical applications. In this way, the key could rely upon the poorly explored field of the metabolomics of the cervicovaginal epithelium. Biotechnological and analytical systems such as dogs and analytics as GC–MS may be alternatives to current tests which leaves us with two good panoramas: 1) a laboratory analytical test; 2) a biotechnological field test; both of which use a "volatile

*Canine Genetics, Health and Medicine*

samples and analytical methods.

discovery of biological scents [34].

origin [6, 23].

ketones, hydrocarbons, aldehydes, organic acids, esters, phenols, etc. Among them, twelve COV were selected as potential oral cancer biomarkers for their use as non-

The above were just some examples of the vast literature that currently exists on the analysis of VOC for the diagnosis of different cancers through non-invasive

As it was mentioned already, the analysis of VOC as cancer biomarkers in diverse biofluids is desirable because it allows a repeated sampling and a non-invasive and quick analysis. In this sense, there is great potential for the development and clinical

The number of studies demonstrating the potential of VOC in cancer diagnosis has increased in the last decades due to analytical chemistry advancements that have made possible the quantitative analysis and comparison of VOC of cellular

From the several analytical techniques that exist, the GC–MS, Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), Proton Transfer Reaction Mass Spectrometry (PTR-MS), Proton Transfer Reaction Time of Flight (PTR-ToF) and Ion Mobility Spectrometry (IMS) have been the most used to separate and identify VOC. These are sophisticated and valuables stationary analytical chemical instruments for the

However, despite the low detection limits and high sensitivity offered by these methodologies, they present certain limitations that have prevented their routine application as screening methods. These require high levels of technical expertise and lengthy instrument run times (tens-of-minutes to hours) for detailed chemical analysis. Most of them, exceptionally high-resolution mass spectrometers, are extremely expensive and require expert maintenance. Furthermore, data interpretation, especially for non-targeted analyzes, may initially take many hours per sample until sufficient statistical results are accumulated to develop a targeted approach. Finally, they require infrastructure and trained personnel for their operation [35].

Dogs have excellent odor detection capabilities in a vast range of fields. Their olfaction is a fundamental sense that let them perceive and comprehend the world around them. Humans have harnessed the canine sense of smell for the detection of different targets as an orthodox manner, such as explosives, land mines, narcotics, missing persons (forensic area), and invasive or endangered species [34, 36]. Right now, in this pandemic situation worldwide, dogs have been trained for COVID-19 early detection [37]. The question arises, why not use the canine olfactory for cancer detection?, nevertheless in the last decades, the use of canine olfaction as a diagnostic tool for identifying preclinical disease, especially cancer in biological samples

Nowadays, there are a considerable number of publications using trained dogs to sort biological samples for follow-up and future diagnostics [31]. Several authors have published research suggesting that dogs can sort dozens of samples, including blind replicates and known control samples in a few minutes and may be able to detect lung, breast, prostate, ovarian, and melanoma cancers by smelling skin

lesions, urine, exhaled breath, and surgically extracted tumors [35, 39].

**7. Dogs (biological noses) as clinical tools in cancer detection**

invasive tools for the possible diagnosis of this cancer [32].

**6. Analytical chemistry (electronic noses) in VOC detection**

application of VOC analysis in the diagnosis and monitoring of cancer [33].

**146**

has increased [34, 38].

biopsy", basically a scent sample, obtained without penetrating the human body at all. Our work team has proposed a device specifically made for this purpose [46, 47].

This device that our research group has developed is a gadget worn by the patient for a defined period, after which is simply stored in a container -provided by us- and mailed to the recipient, avoiding the stress of queuing in a hospital. Our device quickly collects in an *unorthodox manner* the VOC of the genitourinary tract allowing us, to use analytical devices GC–MS system for sample examination, with the surplus of being simple to dispose of after analysis is done. Each sample being scanned in one hour. Afterwards, the metabolic profile is reviewed by an expert to determine if there are any volatile biomarkers associated with the sample.

In this unorthodox scenario (for some people), this device is scanned by a trainer-dog binomial test carried out in seconds. In such an analysis, our gadget eliminates the shock some people could have by watching a dog "deciding their fate". Our results in both scenarios show that a sample's VOC profile result by the analytic test and detected by a trained dog, discriminates between cancerous and non-cancerous samples with more than a 90% sensitivity and specificity. These data are correlated afterwards to histopathological observation as the gold standard, suggesting that the device has a great value proposition [46, 47].

These proposals represent the ideal diagnostic tests for screening CC because they are non-invasive, low cost, accurate and partially portable, therefore meeting the requirements for a good screening test according to WHO. This established that a screening test must be sufficiently accurate to detect the condition earlier than in the absence of screening [48].

Recently another research group in Japan trained a dog to distinguish urine samples from cervical cancer patients from those of the controls, showing that cancer detection by dog sniffing can be a non-invasive, cost-effective screening technique for CC [49]. This report supports our proposal that the canine nose can be used and developed for CC detection.

The use of screening dogs is a real issue, for instance, they play vital roles helping in natural disasters or detecting drug or weapons trafficking as we have mentioned before; in the case of GC–MS itself is used again in the detection of drug trafficking, anti-doping or as a standard test in food products; then, why then should not they be used in the health-care industry? An example is the exhalomic test "Hearts Breath Test for Grade 3 Heart Transplant Rejection detection". Dr. Phillips et al. at Menssana Research Inc. in New Jersey USA developed this FDA approved test. This test detected a specific metabolomic profile and had opened a vast opportunity in the marketing of metabolomic or volatolomic tests [50].

#### **9. A big challenge and an alternative**

Pap test was not specifically developed to detect neither human cervical lesions nor HPV infection [44]. Moreover, it has not been subjected to a rigorous analysis regarding its sensitivity and specificity; however, it is the accepted test for detecting cytomorphological changes in the cervicovaginal epithelium but not for HPV. Epidemiological studies show that HPV detection does not necessarily indicate cancer, so it is considered necessary but not enough for CC development [51].

On the other hand, the CC research has served to define that prior to this type of invasive lesions, there are precursor or pre-invasive lesions as SIL, thanks to epidemiological studies, it has been determined that less than 10% of women infected with HPV will develop CC [52]. So far, it is unknown what factors are indispensable for the progression of these lesions causing *"headaches"* among oncologist and gynecologists alike, for nobody knows which SIL will progress to a more aggressive

**149**

*Canine Detection of the Volatile Organic Compounds Related to Cervical Cancer Cells*

lesion. Many questions result in no concrete answer. Given these facts, the new OMICs area opens the opportunity for the early detection of pre-invasive lesions. Combining analytical and biotechnological procedures as aforementioned will

In summary, our proposals are affordable and accessible for any women and could be an important weapon in this war against CC as a preventive measure deployed by health services, all this granting the public and government depart-

Early detection saves lives. Therefore, it is necessary to implement new and alternative technologies that allow the development of accessible diagnostic methods that cover at least some of the limitations presented by conventional screening tests for the detection of diseases such as cancer, especially Cervical Cancer. The canine detection of odors or volatile profiles emitted by cancer cells is a portable, highly sensitive and specific tool which could be used as a screening alternative (*as fast track*) in marginalized or areas of difficult access (even in the urban regions) to increase coverage in high-risk populations. Additionally, the use of a trained dog for screening could facilite prevention campaigns, saving money,

The CC and its precursor lesions detection is a priority health concern in different countries, therefore having an analytical alternative (GC–MS) and a biological alternative (canine smell) for screening could be a great support technique for conventional methods offering a non-invasive, fast, and accurate detection that can be carried out repeatedly and that would also be useful for monitoring the disease. Applications for these tools extend to providing much needed medical attention for women from cultural backgrounds imposing several prohibitions, deep-rooted cultural taboos, religious beliefs, shame, or lack of health coverages. We thought that a "with a little help" to current methods by using improved, non-expensive and innovative procedures will conduct to accurate and timely diagnostics for this cancer type. Unfortunately, for both analytical and bio-detection methods, there is no consensus in the methodologies used or in the results obtained, thus this is a call to join forces with the scientific and social communities (research groups) for the replication of the studies that lead to the future implementation of these method-

The research team wants to thank every woman who accepted involvement in this project, an early Cervical Cancer diagnosis saves women. To oncologists, gynecologists, and students who collaborated with us to 'put a grain of sand'. In the last moment Miriam Rodriguez was considered as co-corresponding. Finally, to IMSS-CIS and Dr. Tomás Hernández-Quijano for support our research and new

*DOI: http://dx.doi.org/10.5772/intechopen.95773*

ments accept them.

**10. Conclusions**

permit the basis for new portable nanosystems.

time, labor, and lives due to an early diagnosis.

ologies for clinical diagnosis.

**Acknowledgements**

approach for our women.

*Canine Detection of the Volatile Organic Compounds Related to Cervical Cancer Cells DOI: http://dx.doi.org/10.5772/intechopen.95773*

lesion. Many questions result in no concrete answer. Given these facts, the new OMICs area opens the opportunity for the early detection of pre-invasive lesions. Combining analytical and biotechnological procedures as aforementioned will permit the basis for new portable nanosystems.

In summary, our proposals are affordable and accessible for any women and could be an important weapon in this war against CC as a preventive measure deployed by health services, all this granting the public and government departments accept them.

#### **10. Conclusions**

*Canine Genetics, Health and Medicine*

the absence of screening [48].

be used and developed for CC detection.

**9. A big challenge and an alternative**

biopsy", basically a scent sample, obtained without penetrating the human body at all. Our work team has proposed a device specifically made for this purpose [46, 47]. This device that our research group has developed is a gadget worn by the patient for a defined period, after which is simply stored in a container -provided by us- and mailed to the recipient, avoiding the stress of queuing in a hospital. Our device quickly collects in an *unorthodox manner* the VOC of the genitourinary tract allowing us, to use analytical devices GC–MS system for sample examination, with the surplus of being simple to dispose of after analysis is done. Each sample being scanned in one hour. Afterwards, the metabolic profile is reviewed by an expert to

determine if there are any volatile biomarkers associated with the sample. In this unorthodox scenario (for some people), this device is scanned by a trainer-dog binomial test carried out in seconds. In such an analysis, our gadget eliminates the shock some people could have by watching a dog "deciding their fate". Our results in both scenarios show that a sample's VOC profile result by the analytic test and detected by a trained dog, discriminates between cancerous and non-cancerous samples with more than a 90% sensitivity and specificity. These data are correlated afterwards to histopathological observation as the gold standard,

These proposals represent the ideal diagnostic tests for screening CC because they are non-invasive, low cost, accurate and partially portable, therefore meeting the requirements for a good screening test according to WHO. This established that a screening test must be sufficiently accurate to detect the condition earlier than in

Recently another research group in Japan trained a dog to distinguish urine samples from cervical cancer patients from those of the controls, showing that cancer detection by dog sniffing can be a non-invasive, cost-effective screening technique for CC [49]. This report supports our proposal that the canine nose can

The use of screening dogs is a real issue, for instance, they play vital roles helping in natural disasters or detecting drug or weapons trafficking as we have mentioned before; in the case of GC–MS itself is used again in the detection of drug trafficking, anti-doping or as a standard test in food products; then, why then should not they be used in the health-care industry? An example is the exhalomic test "Hearts Breath Test for Grade 3 Heart Transplant Rejection detection". Dr. Phillips et al. at Menssana Research Inc. in New Jersey USA developed this FDA approved test. This test detected a specific metabolomic profile and had opened a vast opportunity in the marketing of metabolomic or volatolomic tests [50].

Pap test was not specifically developed to detect neither human cervical lesions nor HPV infection [44]. Moreover, it has not been subjected to a rigorous analysis regarding its sensitivity and specificity; however, it is the accepted test for detecting cytomorphological changes in the cervicovaginal epithelium but not for HPV. Epidemiological studies show that HPV detection does not necessarily indicate cancer, so it is considered necessary but not enough for CC development [51].

On the other hand, the CC research has served to define that prior to this type of invasive lesions, there are precursor or pre-invasive lesions as SIL, thanks to epidemiological studies, it has been determined that less than 10% of women infected with HPV will develop CC [52]. So far, it is unknown what factors are indispensable for the progression of these lesions causing *"headaches"* among oncologist and gynecologists alike, for nobody knows which SIL will progress to a more aggressive

suggesting that the device has a great value proposition [46, 47].

**148**

Early detection saves lives. Therefore, it is necessary to implement new and alternative technologies that allow the development of accessible diagnostic methods that cover at least some of the limitations presented by conventional screening tests for the detection of diseases such as cancer, especially Cervical Cancer.

The canine detection of odors or volatile profiles emitted by cancer cells is a portable, highly sensitive and specific tool which could be used as a screening alternative (*as fast track*) in marginalized or areas of difficult access (even in the urban regions) to increase coverage in high-risk populations. Additionally, the use of a trained dog for screening could facilite prevention campaigns, saving money, time, labor, and lives due to an early diagnosis.

The CC and its precursor lesions detection is a priority health concern in different countries, therefore having an analytical alternative (GC–MS) and a biological alternative (canine smell) for screening could be a great support technique for conventional methods offering a non-invasive, fast, and accurate detection that can be carried out repeatedly and that would also be useful for monitoring the disease.

Applications for these tools extend to providing much needed medical attention for women from cultural backgrounds imposing several prohibitions, deep-rooted cultural taboos, religious beliefs, shame, or lack of health coverages. We thought that a "with a little help" to current methods by using improved, non-expensive and innovative procedures will conduct to accurate and timely diagnostics for this cancer type. Unfortunately, for both analytical and bio-detection methods, there is no consensus in the methodologies used or in the results obtained, thus this is a call to join forces with the scientific and social communities (research groups) for the replication of the studies that lead to the future implementation of these methodologies for clinical diagnosis.

#### **Acknowledgements**

The research team wants to thank every woman who accepted involvement in this project, an early Cervical Cancer diagnosis saves women. To oncologists, gynecologists, and students who collaborated with us to 'put a grain of sand'. In the last moment Miriam Rodriguez was considered as co-corresponding. Finally, to IMSS-CIS and Dr. Tomás Hernández-Quijano for support our research and new approach for our women.

*Canine Genetics, Health and Medicine*
