Mycoplasmas and Human prostate cancer: An exciting but cautionary note

A recent study of Barykova, et al. [1] described a significant association between Mycoplasma hominis infection and development of prostate cancer. In the study, the authors detected the presence of M. hominis-specific DNA sequences in examining 496 prostate biopsies by PCR obtained from 248 Russian men undergoing cancer diagnosis. The association appeared to be particularly significant in the statistical analysis between M. hominis infection and development of the higher grade prostate cancer. A possible role for mycoplasmas in association with human malignancy was first noted during 1960s. Several studies reported isolation of mycoplasmas from human leukemic bone marrow [2-6]. A majority of the mycoplasmas isolated in the studies were identified as Mycoplasma fermentans. However, the mycoplasmaoncogenesis hypothesis failed to advance because the same mycoplasmas later could also be found in nonleukemic children or adults, although the mycoplasmas appeared to be most frequently isolated from patients with leukemia [7]. Koch’s postulate of identifying the causative agent in an infectious disease by finding a specific pathogen uniquely present in a particular disease process overshadowed the characteristics in both chronicity and multi-factorial nature of the malignant process. Mycoplasmas are a heterogeneous group of very small organisms capable of self-replication. The wallfree microbes can cause a wide variety of diseases in animals. Some mycoplasmas cause respiratory or urogenital diseases in humans. However, many other mycoplasmas chronically colonize our respiratory and urogenital tracts without apparent clinical significance [8]. Various mechanisms including “antigenic variation” may be critical in the ability of these microbial species to evade host antibody responses or other elements of