Expression of calretinin in human mesothelioma cell lines and cell cycle analysis by flow cytometry

Human mesothelioma cell lines were studied concerning the expression of the calcium-binding protein calretinin (CR), and the relation of the DNA index to their cell cycle. The results obtained for cell lines with different mo lphological characteristics, were compared to those from human mesothelial cells transfected with SV40 to escape senescence. Immunocytochemical expres sion of calretinin (confirmed by immunoblot) was observed in all mesothelio ma cell lines but not in the control cells. It is suggested that calretinin is active in the first steps of carcinogenesis in all human mesotheliomas and during several stages in the evolution towards malignancy.