Scientists have discovered a molecular mechanism that allows tumors to develop resistance to chemotherapy. The
molecular mechanism acts as a backup when a gene called p53, that normally helps healthy cells prevent mutations, is missing.
About half of tumors do not have p53.
The backup system is a pathway called MK2. It allows cells with damaged DNA to repair their DNA but does not trigger cell
death if the DNA damage is non-repairable, so cells with damaged DNA continue to divide.
Chemotherapy works by damaging DNA so cells stop dividing. But in the absence of p53, cell division continues, thanks to
the MK2 pathway, and so cancer cells continue to proliferate after chemotherapy. The study shows that cancer cells, like healthy cells, have molecular mechanisms that help them maintain their integrity and
survive.
Researchers identified a
molecule that helps BRCA2 cancer genes resist treatment. The team, from Yale School of Medicine, said that
without the molecule, called co-factor DSS1, the mutated genes cannot do their job of repairing the cancer cells' DNA. BRCA2 is
a tumor suppressor gene that can cause breast and ovarian cancers in as many as 60% of women who have the mutated form.
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