Chemoradiation therapy reduces aldehyde dehydrogenase 1 expression in cervical cancer but does not improve patient survival

Aldehyde dehydrogenase 1 (ALDH-1) is a cancer stem cell marker whose overexpression can predict the prognosis of several human cancers. In this study, we assessed ALDH-1 expression in cervical cancer tissues and investigated the usefulness of ALDH-1 expression levels for the prediction of patient response to chemoradiation therapy and survival. Tissue samples from 74 patients were examined via immunostaining with ALDH-1 antibody before and after chemoradiation therapy. Twenty-nine of the 74 cervical cancer cases exhibited ALDH-1 expression (39.19 %) in the pre-treatment tissue samples; however, only 19 of these 39 cases exhibited ALDH-1 expression (48.72 %) in post-treatment tissue samples, indicating that chemoradiotherapy eliminated the ALDH-1 positive tumor stem cells in cervical cancer. However, patient disease-free survival was not associated with ALDH-1 expression (11.78 ± 1.95 vs. 12.50 ± 1.91 months in ALDH-1-positive and -negative tumors, respectively). This study indicates that the reduction of the cancer stem cell population via chemoradiotherapy may not be sufficient to improve patient survival. Thus, the clinical value of ALDH-1 expression in cervical cancer may need to be re-examined.