Objective：To investigate the expression patterns of CKLF-like MARVEL transmembrane domain containing 5 (CMTM5), a novel tumor suppressor, and epidermal growth factor receptor (EGFR) in prostate cancer (PCa) tissues and cells and to analyze the relationship between CMTM5 and EGFR in PCa.
Methods: The expression patterns of CMTM5 and EGFR in PCa tissues and cells were detected by immunohistochemistry and Western blot, respectively. Results: CMTM5 was highly expressed in 75% (27/36) of benigh prostatic hyperplasia(BPH) tissues but 35.9% (23/64) of PCa tissues (P<0.001). There was a significant difference of CMTM5 expression between the two groups of PCa tissues with different Gleason scores (P=0.003), though its expression was not related to the age, clinical stage, and metastatic situation (P>0.05). EGFR was highly expressed in 57.8% (37/64) of PCa tissues, it had statistical significance between EGFR and CMTM5 expressions in PCa tissues. Furthermore, 23 cases (35.9%) had low CMTM5 expression and high EGFR expression. Western blot showed that CMTM5 was undetectable in PCa cells, in which the EGFR expression was upregulated. Conclusion: The loss of CMTM5 may participate in the progression of PCa resulting from deregulated EGFR.