PTPRJ is downregulated in cervical squamous cell carcinoma.

Squamous cell carcinoma of the uterine cervix (CSCC) is one of the leading causes of death in Indian women. Protein tyrosine phosphatase receptor (PTPR) type J (also known as DEP1) is a recently reported tumour suppressor receptor phosphatase. Critical molecular analysis of PTPRJ/DEP1 (11p11.2) has not performed in CSCC to date. Here, we observed frequent downregulation of cancer samples (=31) at the transcriptional level. Immunohistochemistry revealed concordant low expression of PTPRJ protein with a few samples showing intermediate expression. To probe for the cause of such downregulation of the gene in CSCC (=155), we analysed the copy number and promoter methylation of PTPRJ. The genetic locus showed deletion (14.8%) and the promoter showed methylation (33.5%) of PTPRJ. To the best of our knowledge, for the first time we explored the molecular status of PTPRJ although we observed no statistically significant association with the prognosis of Indian CSCC patients (=76). However, we observed enhanced expression of PTPRJ protein levels that contributes to effective cisplatin chemotherapy in the SiHa cell line. Thus, the present study paves the way for further research into the plausible mechanisms of downregulation of PTPRJ in cervical cancer.