ALDH1 & CD133 in invasive cervical carcinoma & their association with the outcome of chemoradiation therapy.

Background & objectives: Chemoradiation is the standard therapy for locally advanced invasive cervical cancer and response to treatment determines the outcome. Cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) play a role in response to treatment and hence the aim of this study was to evaluate if their levels in pre-treatment biopsies by immunohistochemistry (IHC) could predict response to treatment and outcome. Methods: The study comprised 60 patients with FIGO Stage IIB/III invasive cervical carcinoma treated by chemoradiation. They were divided into two groups based on their clinical outcome: group 1, 30 patients who had no evidence of disease at 48 month follow up and group 2, 30 patients who had disease relapse within 6-12 months of treatment completion. IHC was performed for CSC markers (ALDH1, CD133, Nanog and Oct-4), EMT markers (E-cadherin and vimentin) and squamocolumnar junction (KRT7) markers and H-scores determined. Intergroup comparison was performed. The expression of these markers was also evaluated in histological sections of cervical pre-cancer (CIN1 and CIN3) in comparison to normal cervix. Results: Cervical Intraepithelial Neoplasia grade 3 (CIN3) showed high expression of ALDH1 and KRT7 as compared to normal cervical epithelium. Aldehyde dehydrogenase 1 (ALDH1) and CD133 were overexpressed in 70 and 24 per cent cervical carcinoma cases whereas E-cadherin showed reduced expression in invasive carcinoma as compared to normal controls. ALDH1 overexpression was significantly associated with disease relapse in invasive cervical carcinoma treated by chemoradiation (P<0.01). Interpretation & Conclusions: Determination of ALDH1 levels in pre-treatment cervical biopsies of invasive cervical carcinoma may be useful for prediction of response to chemoradiation, with high levels predicting for a poor response.