The Relation between Exon Variations of KIT Gene and Clinical Pathological Factors of Breast Cancer

Background & Objective: As the most common cancer type, breast cancer has been recognized as the second mortality cause among women. The KIT proto-oncogene is one of the important factors involved in tumor development. The previous findings have demonstrated an increased copy number and overexpression of this gene under the influence of breast cancer development. Materials & Methods: This study aimed to investigate the relationship between the copy number variation (CNV) of all exons of KIT gene and estrogen receptor (ER), progesterone receptor (PR), HER2, P53, stage, tumor size, Ki67, Annexin V, histological type, age, molecular subtype, and node status by surveying breast cancer tissues collected from 64 patients. The CNV exons and clinicopathological variables were assessed by multiplex ligation-dependent probe amplification (MLPA), hematoxylin and eosin (H&E) staining, and immunohistochemistry techniques. Results: Sixty percent of cases in exon 17, 60% in exon 18, and nearly 67% in exon 19 with increased CNVs had a tumor size of 2-5 cm; these results were significant. Also, patients with an increased exon 7 CNV were significantly in stage 3. Other exons did not exhibit significant relation to other clinicopathological variables (P>0.05). Conclusion: Exons 7, 17, 18, and 19 are the key coding domains of tyrosine kinase, involving the activation of various upstream transcription factors that regulate apoptosis, cell differentiation, proliferation, and angiogenesis. Variation in exons can influence drug resistance. The results of this study can contribute to the diagnosis and treatment of breast cancer, although their confirmation requires further examinations.