<P> The presence of Mycoplasma was first reported in samples of cancer tissue in the 1960s . Since then, several studies tried to find and prove the connection between Mycoplasma and cancer, as well as how the bacterium might be involved in the formation of cancer . Several studies have shown that cells that are chronically infected with the bacteria go through a multistep transformation . The changes caused by chronic mycoplasmal infections occur gradually and are both morphological and genetic . The first visual sign of infection is when the cells gradually shift from their normal form to sickle - shaped . They also become hyperchromatic due to an increase of DNA in the nucleus of the cells . In later stages, the cells lose the need for a solid support to grow and proliferate, as well as the normal contact - dependent inhibition cells . </P> <P> Karyotypic changes related to mycoplasma infections </P> <P> Cells infected with Mycoplasma for an extended period of time show significant chromosomal abnormalities . These include the addition of chromosomes, the loss of entire chromosomes, partial loss of chromosomes, and chromosomal translocation . All of these genetic abnormalities may contribute to the process of malignant transformation . Chromosomal translocation and extra chromosomes help create abnormally high activity of certain proto - oncogenes, which caused by these genetic abnormalities and include those encoding c - myc, HRAS, and vav . The activity of proto - oncogenes is not the only cellular function that is affected; tumour suppressor genes are affected by the chromosomal changes induced by mycoplasma, as well . Partial or complete loss of chromosomes causes the loss of important genes involved in the regulation of cell proliferation . Two genes whose activities are markedly decreased during chronic infections with mycoplasma are the Rb and the p53 tumour suppressor genes . Another possible mechanism of carcinogenesis is RAC1 activation by a small GTPase - like protein fragment of Mycoplasma . A major feature that differentiates mycoplasmas from other carcinogenic pathogens is that the mycoplasmas do not cause the cellular changes by insertion of their own genetic material into the host cell . The exact mechanism by which the bacterium causes the changes is not yet known . </P> <Dl> <Dt> Partial reversibility of malignant transformations </Dt> </Dl>

How does mycoplasma survive without a cell wall