Increasing expression of monocarboxylate transporters 1 and 4 along progression to invasive cervical carcinoma

Solid tumor cells are known to be highly glycolytic and, to prevent apoptosis by cellular acidosis, cells increase proton efflux through pH regulators, such as monocarboxylate transporters (MCTs). However, the role of these membrane proteins in solid tumor development and survival is not fully understood. We aimed to evaluate the expression of the MCT isoforms 1, 2, and 4 in a large series of cervical lesions (neoplastic and non-neoplastic) and assess its clinical-pathologic significance. The series analyzed included 29 chronic cervicitis, 30 low-grade squamous intraepithelial lesions, 32 high-grade squamous intraepithelial lesions, 49 squamous cell carcinomas, 51 adenocarcinomas, and 30 adenosquamous carcinomas of the uterine cervix. Analysis of the expression of MCT isoforms 1, 2, and 4 was performed by immunohistochemistry with specific antibodies. Immunoreactions were evaluated both qualitatively and semiquantitatively. We found a significant increase in MCT expression from preinvasive to invasive squamous lesions and from normal glandular epithelium to adenocarcinomas. This is the first study evaluating the significance of MCT expression in lesions of the uterine cervix, including invasive carcinomas, and the results found herein led us to believe that these membrane proteins are involved in the progression to invasiveness in uterine cervix carcinoma.