Do mycoplasmas cause human cancer?

A linkage between mycoplasmas and malignancy was mainly proposed in the 196 0s when human-associated mycoplasmas were becoming of interest given the no vel characterization of the human respiratory pathogen Mycoplasma pneumonia e. Associations with leukemia and other malignancies, however, were largely ascribed to tissue-culture contamination, which is now recognized as a sig nificant potential problem in molecular biology circles. A few epidemiologi cal studies, however, continue to raise concern over such a linkage. As wel l, in vitro data have demonstrated the potential for some mycoplasmas to in duce karyotypic changes and malignant transformation during chronic tissue- culture infestation. As cellular and molecular mechanisms for such transfor mation become studied, a resurgence of interest in this area is inevitable. A role for mycoplasmas in malignancy of any sort is conjectural, but there remains a need to continue with focussed epidemiological and laboratory in vestigations.