They are called oncogenes.
Proto-oncogenes stop cells dividing too often. When a mutation occurs to proto-oncogenes this is when cancer can occur, as there is then no hay-flick limit (normally cells have a limit to how many times then can divide) cells are able to replicate uncontrollably.
how many Mayan codices have been discovered
The ruins of seven cities have been discovered in Delhi.
The best place that one can learn more about oncogenes is the American Cancer Society's official website. The site has a page dedicated to oncogenes and has a list of answers to common questions asked about the gene.
No-one knows, they haven't been discovered
109
10,000
106
oncogenes
10 million
lots.