Somatic Sex: On the Origin of Neoplasms With Chromosome Counts in Uneven Ploidy Ranges

Stable aneuploid genomes with nonrandom numerical changes in uneven ploidy ranges define distinct subsets of hematologic malignancies and solid tumors. The idea put forward herein suggests that they emerge from interactions between diploid mitotic and G0/G1 cells, which can in a single step produce all combinations of mono-, di-, tri-, tetra- and pentasomic paternal/maternal homologue configurations that define such genomes. A nanotube-mediated influx of interphase cell cytoplasm into mitotic cells would thus be responsible for the critical nondisjunction and segregation errors by physically impeding the proper formation of the cell division machinery, whereas only a complete cell fusion can simultaneously generate pentasomies, uniparental trisomies as well as biclonal hypo- and hyperdiploid cell populations. The term "somatic sex" was devised to accentuate the similarities between germ cell and somatic cell fusions. A somatic cell fusion, in particular, recapitulates many processes that are also instrumental in the formation of an abnormal zygote that involves a diploid oocyte and a haploid sperm, which then may further develop into a digynic triploid embryo. Despite their somehow deceptive differences and consequences, the resemblance of these two routes may go far beyond of what has hitherto been appreciated. Based on the arguments put forward herein, I propose that embryonic malignancies of mesenchymal origin with these particular types of aneuploidies can thus be viewed as the kind of flawed somatic equivalent of a digynic triploid embryo.

Cell cycle stress in normal human cells: A route to "first cells" (with/without fitness gain) and cancer-like cell-shape changes

We have presented an in vitro trackable model system, atavistic induced from conservation in our genome, which strongly is applicable to tumorigenesis start and evolution. The inducing factor was death signals to proliferating normal human cells (primary cell strains), which respon-ded by a special type of tetraploidization, chromosomes with 4-chromatids (diplochromosomes, earlier described in cancer cells). The response included cell cycle stress, which prolonged S-period with result of mitotic slippage process, forming the special 4n cells by re-replication of diploid cells, which showed cell division capability to unexpected, genome reduced diploid cells which remarkably, showed fitness gain. This unique response through cell cycle stress and mitotic slippage process was further discovered to be linked to a rather special characteristic of the, 4n nucleus. The nucleus turned, self-inflicted, 90° perpendicular to the cell's cytoskeleton axis, importantly, before the special 4n-division system produced genome reduce diploid cells, we call "first cells", because of fitness gain. These 2n cells also showed the nuclear dependent 90° turn, which in both cases was associated with cells gaining cell shape changes, herein illustrated from normal fibroblastic cells changing to roundness cells, indistinguishable from todays' diagnostic cancer cell morphology. This 3-D ball-like cell shape, in metastasis, sque-ezing in and out between (?) endothelial cells in the lining of blood veins during disbursement, would be advantageous.