Background: The human leucine-rich repeats and immunoglobulin-like domains (LRIG) protein family comprises LRIG1, 2, and 3. LRIG1 negatively regulates growth factor signaling and is a proposed tumor suppressor. In early stage uterine cervical carcinoma, expression of LRIG1 is associated with good survival. Less is known about the function and expression of LRIG2; it has not been studied in cervical carcinoma, previously.
Materials and methods: LRIG2 expression was studied by immunohistochemistry in 129 uterine cervical squamous cell carcinomas and 36 uterine cervical adenocarcinomas. Possible associations between LRIG2 immunoreactivity and patient survival were evaluated.
Results: In early-stage squamous cell carcinoma (stages IB-IIB), high expression of LRIG2 was associated with poor survival (Kaplan-Meier, log-rank, p=0.02). The 10-year survival rate for patients with high expression of LRIG2 was 60%, compared to 87% in patients with low expression (odds ratio 0.22, 95% CI 0.07-0.64). In multivariate analysis including the previously studied tumor suppressor LRIG1 and clinical stage, LRIG2 emerged as an independent prognostic factor (odds ratio 0.22, 95% CI 0.09-0.50). For patients with both high expression of LRIG2 and low expression of LRIG1, the 10-year survival rate was only 26% compared to 66% for the remaining study population. There was no correlation between LRIG2 expression and prognosis in the limited adenocarcinoma series.
Discussion and conclusion: LRIG2 appears to be a significant predictor of poor prognosis in early-stage squamous cell carcinoma of the uterine cervix. A combination of high LRIG2 expression and low LRIG1 expression identified women with a very poor prognosis.