Expression of metallothioneins in cutaneous squamous cell carcinoma and actinic keratosis

Metallothioneins (MT) are low-molecular weight proteins implicated in heavy metal detoxification, zinc and cooper homeostasis and cell protection against free radicals. In variety of cancers MT-overexpression was shown, but there are just a few studies on the role of MT in skin carcinogenesis. Current study was undertaken to evaluate MT and Ki-67 expression in pre-cancerous skin lesions as well as in fully developed skin cancers. 73 squamous cell carcinomas (SCC), 23 actinic keratoses (AK) and 20 normal skin samples were included in the study. In obtained paraffin sections immunohistochemical reactions were performed. MT-expression in SCC (mean 2.89 ± 1.83) was significantly higher than in AK (mean 1.69 ± 1.26)(p = 0.006) and higher than in normal skin (mean 2 ± 0.79) (p = 0.0075). The MT-expression positively correlated with Ki-67 expression (R = 0.28; p = 0.017) in SCC and in AK (R = 0.49; p = 0.018). Various clinico-pathological variables, e.g. morphology, size of lesions and the depth of neoplastic infiltration were not associated to MT-expression in both SCC and AK. The grade of histological differentiation of SCC correlated positively with Ki-67 antigen (p < 0.001) and did not correlate with MT-expression (p = 0.06). Ki-67 expression was higher in SCC and in AK than in healthy skin (p = 0,003). In SCC and in AK expression of Ki-67 antigen correlated positively with MT-expression (respectively p = 0.017 and p = 0.018). MT may serve as a good markers of proliferation in SCC and AK. MT-overexpression in SCC may suggest a potential role of MT in skin carcinogenesis.