The most important discovery that came out of my lab, in my mind, happened in 1978-79. I’d been influenced by previous work of a man named Bruce Ames who was and then still is, at the University of California, Berkeley and who demonstrated in 1975-76 that if you looked at a whole series of carcinogenic chemicals the ability of these cancer-causing chemicals to trigger cancer in mice or rats was related, was correlated to their ability to inflect damage on DNA and therefore there arose in my mind and obviously in the minds of many others, the notion that to the extent of carcinogenic molecules can cause cancer - they do so through their ability to damage DNA. And a deduction from that is that within the DNA of cancer cells, there must lie damaged genes - mutant genes. And moreover, these damaged genes, one could deduce, must be responsible for the abhorrent behavior of the cancer cells. And so in 1978 a new graduate student came into my laboratory and I began to urge him to work on that problem. In truth, he had little choice because he came to me from another lab in the MIT Biology Department where his initial interactions with his professor/mentor did not go well, so he was stuck now with a second mentor – myself – and he couldn’t afford to have this second marriage fail. And so he began a long and convoluted series of experiments, experimentally very challenging. His name was Tao-shih Hsieh, in which he would take DNA from chemically transformed cells and put that DNA into normal cells. When I say chemically transformed cells, I mean cells that were converted from being normal to being cancerous through exposure to a chemical carcinogen, such as the chemicals that are present for example in cigarette smoke tar. And the idea was if one can transfer the information from being a cancer cell from the chemically transformed cells into the normal cells - that would prove that in fact the information from being a cancer cell resided within the DNA within the genes of the cancer cell. And moreover, if you did the same experiment, by preparing DNA from normal cells and putting it into a normal cell without observing the change in the behavior of the recipient cell - that would prove that not only is the behavior of the cancer cell orchestrated by DNA, but it’s orchestrated by an element or elements of DNA, a gene segment or a gene, which is present in the cancer cell but not in the corresponding normal cell and those were the experiments that we did in 1978-79. To be honest, I didn’t do them; I just looked over his shoulder and gave him advice from time to time. A little bit of which he actually took. So by 1979 we were able to report that one could actually do such an experiment and I say this was in my own mind, the most important thing to ever come from my lab, because it demonstrated the fundamental concept that cancer cells were, as one had speculated, genetically abnormal, and that the genetic abnormality was responsible for their abnormal behavior.

Robert "Bob" Weinberg is Daniel K. Ludwig Professor for Cancer Research and director of the Ludwig Cancer Center at MIT, an American Cancer Society Research Professor, and is a founding member of the Whitehead Institute for Biomedical Research.

In 1982 he was one of the scientists to discover the first human oncogene, Ras, which causes normal cells to form tumors, and his lab also isolated the first known tumor suppressor gene, Rb.

He co-authored with Douglas Hanahan the landmark "Hallmarks of Cancer" paper in 2000, which laid out the six requirements for a healthy cell to become cancerous.