For long, medical care has been blamed for the racial clinical difference on the disparity of breast cancer between white women and black women, first observed in the '70s in US, with the emergence of the new technique of mammography.

But many subsequent researches found that African and American women with African ancestry are more likely to develop breast cancer before menopause and die of it, compared to white women. The average age of breast cancer development was found to be 46 in African American women and 57 for their white counterparts. One research found this age was 43 in the case of the Nigerian women compared to 64 for British ones. In Nigeria, over 70% of the cases were under 50, while in Britain this percentage was under 20%. This is worrisome, as women operated for breast cancer before the menopause had a much higher percentage of relapse.

But a new research published in the British Journal of Cancer and carried on 293 women in the London borough of Hackney discovered that black women were on average actually 21 years younger than white women when developing breast cancer!

The 102 black subjects were found with breast cancer at an average age of 46, compared to the 191 white subjects, who were diagnosed on average at the age of 67. The team took into account external factors, like the socio-economic ones. Black women not only developed breast cancer earlier, but they experienced smaller, more aggressive types.

"These are less likely to respond to the new, well-publicized cancer drugs such as Herceptin. We are thinking along the lines that these results are down to biological differences. More research is needed to see if this stands up, and then to work out what the implications are," lead researcher Dr Rebecca Bowen told BBC News.