During normal mitosis, sister chromatids separate into two identical daughter cells. In meiosis is a diploid cell (2N) duplicates its DNA once and undergoes two rounds of cell division to produce four haploid (1N), germ cells that promotes the recombination of large expanses of chromosomal DNA, potentially similar in size to those lost or gained in cancer In meiotic division, homologous chromosomes are held together by cohesions, and after resolution of chiasma (the recombination crossover points with the other chromosome pair), the homologous chromosomes are segregated together.Meiomitosis is an aberrant cellular division pathway through which daughter cells following mitosis inherit partially expressed meiotic machinery. In these cells chiasma occurs and sister chromatids are partly held together by cohesions; when cell division occurs, the sister chromatids are sheared and mis-segregated which results in an aneuploid state.
Role of Meiomitosis in Cancer
Melanoma may be prone to meiomitosis due to the high frequency of testis antigen that is expressed in tumor cells, two of which are known meiosis proteins. Melanoma tumor cells that replicate via meiomitosis may become immortal due to the expression of telomerase but, this comes at the cost of meiotic proteins and genomic instability. Instability is different from tumor to tumor and even from cell to cell. Research suggests that genomic instability affects the cancer cells ability to metastasize. Cells able to affectively metastasize are more genomically stable than the rest of the local tumor bulk.