Lung cancer is the most commonly diagnosed
cancer and the most frequent cause of death worldwide.
Tesmin (testis‑specific metallothionein‑like
protein; MTL‑5) is a 60‑kDa
protein which has cysteine‑rich motifs (CXC domain), characteristic of
metallothioneins (MTs).
Tesmin expression has been observed in germ cells during spermatogenesis, oogenesis and also in various cell nuclei after exposure to
heavy metal ions. Yet, the role of
tesmin in
carcinogenesis is unknown. The aim of the present study was to evaluate the localization and intensity of
tesmin expression in non‑small cell
lung cancer (NSCLC) and its association with the clinicopathological data of patients. A total of 121 cases of NSCLC and 20 cases of non‑cancerous tissue samples from the
surgical margin (control) were used for immunohistochemistry (IHC). In addition, 20 cases of frozen NSCLC tissues and 20 cases of control were used for the in vivo study. Normal lung fibroblasts (IMR‑90) and
lung cancer cell lines NCI‑H1703 (lung
squamous cell carcinoma), NCI‑H522 and A549 (both
adenocarcinomas of the lung) were used for western blot analysis (WB) and RT‑PCR studies. Positive cytoplasmic
tesmin expression was observed in 88.42% of the examined cases of NSCLC. Statistical analysis showed increased IHC
tesmin expression in
cancer cells compared to that noted in the controls. In addition, MTL5
mRNA and WB
tesmin protein expression were also higher in
cancer cases compared to the controls. A positive correlation between
tesmin and Ki‑67 IHC expression was demonstrated (r=0.32; P<0.001). Higher WB
tesmin expression was also associated with shorter overall survival (P<0.05, Mantel‑Cox test). The in vitro study revealed higher
tesmin protein (WB) and MTL5 (qPCR) in
lung cancer cell lines compared to the lung fibroblast control cell line. Higher
tesmin expression in
cancer cells compared to control cells may suggest a role of
tesmin in NSCLC
carcinogenesis. A positive correlation between
tesmin and Ki‑67 could indicate a possible role of
tesmin in the proliferation of NSCLC.