Calcium-Activated Potassium Channel (KCNMA1) as Biomarker of Pre-Invasive and Invasive Cervical Cancer

Several ion channels including calcium-activated potassium channels like KCNMA1 have been proposed as tumor markers and therapeutic targets for various cancers. KCNMA1 channel expression has been found to be progressively increasing with increasing severity of the lesion in samples collected retrospectively. Therefore, we aimed to prospectively study the mRNA and protein expression of KCNMA1 in pre-invasive and invasive cervical cancer.

Sixty women were recruited to the study and allocated equally (n = 15) into four groups on the basis of histopathology, i.e., control (Group 1), cervical intraepithelial neoplasia CIN1 (Group 2), CIN2/CIN3 (Group 3) and invasive cervical carcinoma (Group 4). Real-time PCR and immunohistochemistry were used for assessing mRNA and protein expression of KCNMA1 at mRNA and protein level, respectively.

The mean KCNMA1 mRNA levels in Groups 1, 2, 3 and 4 were 0.23 (SD ± 0.58), 271.40 (SD ± 1050.21), 298.84 (SD ± 1153.33) and 326.54 (SD ± 861.97), respectively (p = 0.039). Protein expression was positive in 34% in CIN1, 80% in CIN2/CIN3 and 100% in the cervical cancer group (p = < 0.001). On subgroup analysis in cervical cancer, KCNMA1 mRNA and protein expressions were higher in tumor size > 4 cm, poorly differentiated tumors, deep stromal invasion and non-keratinizing squamous cell carcinoma.

KCNMA1 protein and mRNA expressions were significantly different between the groups studied. The expression was found to increase with severity of lesion. To the best of our knowledge, this is the first prospective study on KCNMA1 channels in cervical pre-cancer and cancer. Further exploratory studies can be done to establish KCNMA1 as a prognostic biomarker.