The general assumption that a tumour cell's behaviour is guided largely by its DNA sequence may be incorrect.

John Dick at the University of Toronto in Canada and his colleagues grew 150 cell populations from individual, labelled cancer cells taken from ten patient-derived colorectal-cancer samples. The researchers transplanted these cells into mice, then tracked their genetics and behaviour as the grafts grew. Tumour-cell clones from the same cell line differed widely in their growth patterns, ability to seed new tumours and response to the cancer drug oxaliplatin.

The results suggest that factors beyond the DNA sequence — such as differences in the chemical groups attached to it, which influence gene expression, or environmental influences — shape tumour-cell conduct.

Science http://dx.doi.org/10.1126/science.1227670 (2012)