HER2Ile655Val Polymorphism and Risk of Breast Cancer

HER2 plays a vital role in the development and progression of several types of human cancer, so the HER2 becomes one of major targets for HER2-positive breast cancer treatment. Several reports have shown that the HER2 oncogene expression relates to clinicopathological factors in cancer patients. HER2Ile655Val single nucleotide polymorphism associates with malignant tumors, including prostate cancer, colorectal cancer, osteosarcoma, gastric cancer, uterine cervical carcinoma, fibroadenoma, and breast cancer. To understand the precise association, this chapter was described to estimate the association between HER2Ile655Val single nucleotide polymorphism and susceptibility to breast cancer. Our findings suggest that the Val allele in HER2 codon 655 single nucleotide polymorphism is strongly associated with the risk of breast cancer. HER2Ile655Val single nucleotide polymorphism might also be a susceptibility factor that favors early-onset breast cancer.