..genes in this microbiome — [of bacteria and fungi] exchanging messages with genes inside human cells — may be involved with cancers of the colon, stomach, esophagus and other organs...The idea that people in different regions of the world have co-evolved with different microbial ecosystems may be a factor — along with diet, lifestyle and other environmental agents — in explaining why they are often subject to different cancers.The article lists a number of further ideas, involving various classes of small or micro RNAs, here's a great sentence:
...Most DNA…was long considered junk … Only about 2 percent of the human genome carries the code for making enzymes and other proteins…These days “junk” DNA is referred to more respectfully as “noncoding” DNA, and researchers are finding clues that “pseudogenes” lurking within this dark region may play a role in cancer.
...With so much internal machinery, malignant tumors are now being compared to renegade organs sprouting inside the body…[they] contain healthy cells that have been conscripted into the cause. Cells called fibroblasts collaborate by secreting proteins the tumor needs to build its supportive scaffolding and expand into surrounding tissues. Immune system cells, maneuvered into behaving as if they were healing a wound, emit growth factors that embolden the tumor and stimulate angiogenesis, the generation of new blood vessels. Endothelial cells, which form the lining of the circulatory system, are also enlisted in the construction of the tumor’s own blood supply.
...other exotic players: lincRNA, (for large intervening noncoding), siRNA (small interfering), snoRNA (small nucleolar) and piRNA (Piwi-interacting (short for “P-element induced wimpy testis” (a peculiar term that threatens to pull this sentence into a regress of nested parenthetical explanations))).