Cancer researcher Steven Offer, PhD investigates the genetic factors that increase the risk of a toxic reaction to the cancer drug Fluorouracil (5-FU). 5-FU, used since the 1970s to treat many cancers including colorectal, stomach, breast and cervical cancer, can be toxic to certain patients. While many cancer drugs can be toxic, what sets 5-FU apart is that severe illness and death is largely preventable.

"One thing that strikes home is these patients are dying because of their treatment…and not necessarily dying because the cancer has progressed," Offer said.

Current genetic tests typically screen for four or fewer variants. However, work by Offer and others have identified more than 50 additional genetic variants that increase the risk of severe toxicity to 5-FU. Offer says ideally, medical systems should pre-screen for these additional variants that can lead to the deadly reaction.

Full gene sequencing is one approach to accomplish this, but these tests are not widely available. Offer says that may be due to the added cost and infrastructure.

One issue, Offer says, is that the studies used to identify the four most common variants in pre-screening were conducted in patient populations that were mostly white, whereas the additional variants are more likely to be found in under-represented populations. This leaves those populations more vulnerable.

View the full article from the Canadian Broadcasting Company here:
https://www.cbc.ca/amp/1.7039145