England's National Health Service (NHS) has begun offering an expanded form of genetic testing to cancer patients from minority ethnic backgrounds, addressing a long-standing gap in pre-chemotherapy screening. The existing tests, which help doctors calibrate chemotherapy doses to minimise severe side effects — including potentially fatal reactions — previously screened only for four variants of the DPYD gene found predominantly in people of white European ancestry. A fifth variant, more common among people of Black and minority ethnic heritage, has now been added to the screening panel, meaning patients who previously could have been incorrectly cleared for standard doses will receive more accurately tailored treatment. Since the updated test was introduced at Manchester University NHS Foundation Trust last September, three patients from minority ethnic backgrounds have already received adjusted chemotherapy doses as a result. Health officials described the move as the first concrete clinical response to evidence that cancer safety protocols were designed around white European genetics, leaving other communities at greater risk.