Cancer is a complex and multi-factorial disease that arises from the interplay between a genetic component often involving several genes, and environmental determinants such as diet, lifestyle, or chemical exposure. Although some cancers—a very small fraction which occurs very rarely in the population—can be attributed almost completely to genetics, the majority of cases are a result of the interaction of environmental factors with the individual’s genetic make up. Over the years, scientists have been able to demonstrate that variations in our genes affect how our bodies respond to environmental agents, and in turn, influence our predisposition to developing cancer. Smoking, for example, has long been established to be strongly associated with lung cancer, but not all smokers will suffer from this particular cancer type. By identifying which genes and which variations in such genes are able to significantly alter individual risk for the disease, we can harness them as tools to distinguish genetically susceptible subgroups and prevent cancer development through intervention strategies.
Through the aid of the Philippine Council for Health Research and Development under the Department of Science and Technology, the Philippine Cancer Genetics Study Group was born. Established in 2002 and consisting of several clinical and research institutes (Institute of Human Genetics, Institute of Clinical Epidemiology, UP College of Medicine-Philippine General Hospital, Jose Reyes Memorial Medical Center, Lung Center of the Philippines, Ospital ng Maynila Medical Center, East Avenue Medical Center, Medical Center Manila and Corazon Locsin Montelibano Memorial Regional Hospital), the group embarked on a molecular epidemiology project that aimed to evaluate the potential of genetic polymorphisms—changes in the DNA sequence that occur in at least 1% of the population—in selected candidate genes as biomarkers or indicators of disease risk, for four of the leading cancer types in the country: lung, breast, colon-rectum and oral cavity. By relating these polymorphisms with epidemiological factors such as age, sex, diet, ethnicity and chemical exposure, we are able to gather a more accurate assessment of the association between genetic polymorphisms and cancer risk.
Since its inception, the Philippine Cancer Genetics Study Group has analyzed over 1,900 subjects for sixteen polymorphisms in seven different genes. Not only has the project led to the identification of yet unreported risk and protective epidemiological factors for the four leading cancer types studied, but also found prospective biomarkers that could be developed as indicators of cancer risk that are specifically targeted for the Philippine population. To date, the group continues to conduct further analyses on the data obtained from the study, hoping to one day find clues to unraveling the molecular epidemiology of cancer among Filipinos. Dr Eva Cutiongco- de la Paz, project leader of the Cancer Project, is optimistic that with the strong collaboration between the geneticists and cancer specialists, there will be a better future for our cancer patients in the Philippines.