Cells from an advanced malignant tumor most often have very abnormal chromosomes, and often an abnormal total number of chromosomes. Why might this occur?

Question

aaronq · Answer

mutations

anonymous · Answer

The total number of chromosomes might be altered by non-disjunction - in this case two copies of a chromosome go into one cell. if this confers a growth advantage then the cell will tend to maintain the higher number of chromosomes. Abnormalities can come from breaking and rejoining of chromosomes leading to fusion proteins which make the cells grow faster - an example being BCR-ABL which is common in chronic myeloid leukemia (CML). So I have to agree that the cells carry mutations but I contend that the mutations are selected for ie they are advantageous to the cell.