Racial Differences in Oncogene Mutations Detected in Early-Stage Low-Grade Endometrial Cancers

Abstract

ObjectiveTo describe the pattern and frequency of oncogene mutations in white and African American women with endometrial cancer and to determine if racial differences in oncogene mutations exist among women with pathologically similar tumors.MethodsPatients with endometrial cancer from a large urban hospital were identified through medical records, and representative formalin-fixed paraffin-embedded tumor blocks were retrieved. The study sample included 150 patients (84 African Americans) who underwent total abdominal hysterectomy for endometrial cancer. The Sequenom MassARRAY system and the OncoCarta Assay version 1.0 (Sequenom) were used to test for 238 mutations in 19 common oncogenes. The χ2test and the Fisher exact test were used to assess differences in distribution of variables by race and oncogene mutation status.ResultsThere were 20 mutations identified in 2 oncogenes (PIK3CAandKRAS) in tumors from 19 women (12.7%). Most of the mutations were found inPIK3CA(16/20). Thirteen percent of endometrioid tumors harbored mutations (11PIK3CAand 2KRAS) as did 29% of the malignant mixed Mullerian tumors (3PIK3CAand 1KRAS). There were no observed mutations in serous, clear cell, or mucinous tumor types. Among low-grade endometrioid cancers, tumors from African American patients were significantly associated with harboring either aKRASorPIK3CAmutation (P= 0.04), with 7PIK3CAmutations and all 4KRASmutations identified in African American women.ConclusionsThis study provides preliminary evidence that oncogene mutation frequency of some subtypes of histologically similar endometrial carcinoma differ by race. Additional studies are needed to further explore this phenomenon in patients with endometrial carcinoma.