Endometrial Cancer Insulin-Like Growth Factor 1 Receptor (IGF1R) Expression Increases with Body Mass Index and Is Associated with Pathologic Extent and Prognosis.

BACKGROUND: Obesity is a main risk factor for endometrial carcinoma (EC). Insulin-like growth factor 1 receptor (IGF1R) expression may influence this association.
METHODS: IGF1R IHC was performed on a tissue microarray with 894 EC and scored according to the percentage and intensity of staining to create immunoreactivity scores, which were dichotomized into low and high IGF1R expression groups. Logistic regression modeling assessed associations with body mass index (BMI), age, histology, pathologic extent of disease (pT), and lymph node metastasis (pN). Overall survival (OS) and disease-free survival (DFS) were compared between IGF1R expression groups using Kaplan-Meier curves and log-rank tests.
RESULTS: The proportion of patients with high IGF1R expression increased as BMI (<30, 30-39, and 40+ kg/m(2)) increased (P = 0.002). The adjusted odds of having high IGF1R expression was 1.49 [95% confidence interval (CI), 1.05-2.10, P = 0.024] for patients with BMI 30 to 39 kg/m(2) compared with <30 kg/m(2) and 1.62 (95% CI, 1.13-2.33, P = 0.009) for patients with BMI 40+ kg/m(2) compared with <30 kg/m(2). High IGF1R expression was associated with pT and pN univariately and with pT after adjusting for BMI, pN, age, and histologic subtype. DFS and OS were better with high IGF1R expression, P = 0.020 and P = 0.002, respectively, but DFS was not significant after adjusting for pT, pN, and histologic subtype of the tumor.
CONCLUSIONS: There is an association between BMI and EC IGF1R expression. Higher IGF1R expression is associated with lower pT and better DFS and OS. IMPACT: These findings suggest a link between IGF1R EC expression and obesity, as well as IGF1R expression and survival. ©2015 American Association for Cancer Research.