In a mind-bending announcement, researchers from Hopital St. Louis have announced that they analyzed a squamous-cell skin cancer in a kidney transplant recipient and found that the cells came from the donor kidney. The donor kidney cells carry a mutation which predisposes to the development of cancer but the transplant itself did not develop cancer (i.e., kidney cancer). Rather some kidney cells seemingly migrated to the skin, became skin cells and then developed skin cancer. The actual article is in the public domain (with minimal tweaking) and can be viewed here. Fortuitously the transplanted kidney had been biopsied in the recipient years before the skin cancer developed; when its genome was analyzed, it contained the identical mutations found in the skin cancer. The researchers and commentators on the article haven’t fully absorbed the full meaning of this but clearly we just found out that we knew much less about cell biology than we thought we did. Dr. Stark comments: “This discovery is not as serendipitous as dropping Penicillium mold onto a petri dish containing bacteria, but it’s close. A whole new field of biology has just been created.”