Scottish scientists have shed light on the connection between deprivation and breast cancer survival, confirming that the link is mirrored at a genetic level.
Women from poorer backgrounds are known to be less likely to survive breast cancer and scientists at the University of Dundee have now identified a link between deprivation and the p53 tumour suppressor gene that may help to explain this trend.
In healthy people, p53 - the so-called "guardian of the genome" - plays a key role in preventing cells from becoming cancerous.
But the Scottish team found that women from deprived backgrounds were more likely to have faulty p53, and that those who did were more likely to relapse and die from breast cancer.
The researchers studied frozen tissue samples from 246 women who had been treated for breast cancer between 1997 and 2001, comparing the state of their p53 genes against their socio-economic background, as determined by their postcodes.
Writing in the British Journal of Cancer, they revealed that women from the lowest socio-economic group were much more likely to relapse and die than their wealthier counterparts.
Furthermore, poorer breast cancer survival for the most deprived patients tended to be associated with p53 faults.
Dr Lee Baker, from the university's Department of Surgery and Molecular Oncology, revealed: "There are two ways that p53 mutations can come about. One is as a result of genetic predisposition and the other is as a result of lifestyle.
"Smoking, drinking, poor diet etc can lead to p53 mutations and are more common in women from lower socio-economic groups, who are also more likely to experience a recurrence of the disease and to die as a result of breast cancer."
The scientist explained that the team found a "strong link" between p53 and deprivation, and between p53 faults and breast cancer recurrence and death.
"As a social issue, it shows that if we lift people up the deprivation scale, then they will be less likely to have problems with their p53 gene and go on to develop breast cancer," he suggested.
Dr Baker noted that deprivation alone does not cause breast cancer. However, it "can affect prognosis when p53 is damaged as a result of lifestyle choices commonly associated with deprivation".
Alastair Thompson, professor of surgical oncology at the University of Dundee, added: "Although the data will in future need confirmation in additional studies, this paper suggests, for the first time, an underlying biology, based around the p53 gene, explaining why women with breast cancer from the most deprived backgrounds do worst in terms of survival."
Ed Yong, head of health evidence and information at Cancer Research UK, commented: "We know that people from poorer backgrounds are more likely to die from some cancers, but it's interesting to see this difference mirrored at a genetic level. These results will need to be confirmed in other studies but they suggest that there could be important biological differences between the cancers developed by richer and poorer women.
"This finding also reminds us that poverty is a big issue in cancer. This is why Cancer Research UK's Commit to Beat Cancer campaign is calling for strong government action so that all cancer patients have the best possible outcome, including tackling the differences between different social groups."
How different types of bread impact cancer risk