Polyploidy and reduction divisions in cancer and mosquito gut cells

Several articles in a recent issue of this journal have called attention to a possible way by which cancer cells can evade death and become resistant to treatments (discussed in Erenpreisa et al., 2008; Wheatley, 2008). Some cancer cells duplicate chromosomes inside their nucleus without undergoing mitosis. The resultant large polyploid cells remain quiescent, but eventually a small percentage undergoes reduction divisions to form diploid or pseudo-diploid cells which then proliferate via normal mitosis, and which sometimes are more resistant to treatment than were the original cells (e.g., Puig et al., 2008). However, this is not a specific trait of cancer cells because somatic reduction divisions regularly occur in non-cancerous cells, the best-studied example being cells of the mosquito gut.