How Cancer Cells Differ
Discussion of cancer cells as distinguished from normal cells in appearance and behavior.C. Norman Coleman, MD
Director, Radiation Oncology Sciences Program
National Cancer Institute
and
Robert Weinberg, PhD
Daniel K. Ludwig Professor for Cancer Research
Massachusetts Institute of Technology
NORMAN COLEMAN, MD
A cancer cell may look completely normal. Some of the chronic leukemias, chronic lymphocytic leukemia, you can't tell it from a normal cell by looking at it; there are just more of them. Some cells, they look wild.
Rather than a nice, round nucleus, the nucleus is really bizarrely shaped. There'll be great disparity in cell sizes; there'll be some big cells and some small cells. So you have a sense of chaos.
ROBERT WEINBERG, PhD
We could ask how do cancer cells differ from normal cells? Well, first of all they look different, they have different shapes. The nuclei in the center of the cells is often much larger, even the sub-nuclear structures are different. The metabolism of cancer cells is often very different from normal cells; they will pump in a lot more glucose than normal cells. The lifespan of the cancer cells can often be much longer, they have immortalized replicatively and they can proliferate for an unlimited extent. In fact, the more we look for details of the biochemical structures inside cancer cells the more we realize they are different from normal cells in dozens of ways, not just those ways that are visible to us under the microscope.
NORMAN COLEMAN, MD
Cell immortalization means a cell keeps on going, that it'll keep on dividing, it won't be deleted. So it has lost its ability to disappear either by apoptosis - programmed cell death -- or by terminal senescence, which means it just sits there and stops dividing. Immortal cells can keep on dividing, keep on dividing. They aren't necessarily cancer; they can be local and just produce a lump. So immortalization plus the ability to metastasize is what produces cancers.