ABSTRACT: Background: Breast cancer has emerged as a cancer with the highest incidence among women in Indonesia. Data has shown that there has been an increased incidence of early-onset breast cancer in developing countries. One of the genes that estimated to play a role in early-onset breast cancer is FGFR2 polymorphism, in which the strongest association is at FGFR2 rs2981582 (C>T). However, there are contradictory results in different studies involving different races. Objective: To determine the proportion and association of SNP FGFR2 rs2981582 genetic variation on breast cancer patients in Yogyakarta. Methods: Blood DNAs of 206 breast cancer patients aged <40 years and >55 years from 2006 to 2012 in Sardjito Hospital were collected before surgery and analyzed by PCR-RFLP. Chi-square analysis was performed to see the relationship between the genotype distribution of age <40 years and those aged> 55 years and compared with the HapMap populations. Comparison of the genotype proportion of each age group was done by z-score analysis. Risk relationships were analyzed using odds ratios. Results: The most frequent genotype in breast cancer patients Yogyakarta is CT, followed by CC, and then TT. TT genotype and T allele are more frequent in the age of onset <40 years compared to the age of onset> 55 years (P <0.05). In addition, the TT genotype and T allele were associated with an increased risk of breast cancer onset <40 years of 2.63 and 1.64, respectively, compared to the CC genotype and allele C. Conclusion: The findings of this study indicate that the SNP rs2981582 may be associated with an increased risk of early-onset breast cancer in Yogyakarta. Keywords: breast cancer, early-onset breast cancer, polymorphism, FGFR2, rs2981582
