MERKEL CELL-CARCINOMA - IN-VITRO AND IN-VIVO CHARACTERISTICS OF A NEWCELL-LINE

Background. Few studies exist that describe Merkel cell carcinoma (MCC ) growth characteristics in vitro, in vivo, or both. Objective: Our pu rpose was to evaluate the pathologic features of MCC implanted into at hymic mice and to determine cytogenetic abnormalities in the establish ed cell line. Methods. Tumor tissues from a patient with MCC were grow n in culture. Cultured cells were karyotyped and inoculated subcutaneo usly into athymic mice. Nude mouse tumors were reimplanted into other athymic mice. Tissues from the primary skin tumor and the nude mouse t umor were processed for light and electron microscopy and immunocytoch emistry. Results. The cell line showed a doubling time of 64.8 hours. Xenografts of 4 x 10(6) cells produced tumors in athymic mice with a d oubling time of 16.1 days. The nude mouse tumors showed pathologic fea tures similar to those of the primary skin tumor. Cytogenetic studies showed a t(1;17) (p36;q21) translocation in 100% of the cells. Conclus ion: MCC implanted into athymic mice retained the pathologic features of the primary skin tumor and behaved aggressively. The t(1;17) (p36;q 21) translocation may be a marker of an aggressive phenotype.