Polymorphism P21 Ser31Arg; Study of Early Onset Breast Cancer Risk in Yogyakarta
ABSTRACT: Introduction: Breast cancer that occurs in young age is more progressive and has poorer prognosis than late onset breast cancer. Genetic studies have been conducted to find the risk factor for early onset breast cancer, and one of them is P21 Ser31Arg polymorphism. P21 Ser31Arg polymorphisms have been observed in many ethnics but the results are still contradictive. The study of P21 Ser31Arg have not been done in Indonesia. P21 Ser31Arg polymorphism is thought to have role in early onset breast cancer although the role is not clear yet. Purpose: To examine the proportion of P21 Ser31Arg polymorphisms and the relationship of P21 Ser31Arg polymorphisms with age of onset of breast cancer patient in Yogyakarta. Methods: DNA from blood samples obtained from breast cancer patients were extracted to test for polymorphism using PCR-RFLP method. Samples were taken from two age groups; early onset breast cancer patients (<40 years old) and breast cancer patients aged more than 55 years old from RS Dr. Sardjito in 2006-2012. Pearson�s Chi-Square and Z-test were used to check the difference of P21 Ser31Arg polymorphism between two age groups of breast cancer and to compare the difference of genotype proportion with the Hapmap population. Results: Genotype C/A is the most common genotype found in breast cancer patients, followed with C/C, and then A/A. Genotype A/A and alel A is more frequent in breast cancer patient aged <40 years than >55 years, although it�s not statistically significant (p>0,05). Conclusion: This study shows that P21 Ser31Arg polymorphism is not related with early onset breast cancer incidence in Yogyakarta. Keywords: Polymorphism, P21 Ser31Arg, PCR, RFLP, early onset breast cancer.
