Lack of association between bovine leukemia virus and breast cancer in Chinese patients

Since Francis Peyton Rous’s landmark study of identifying avian oncogenic virus, seven viruses have been found to cause 10–15 % of human cancers worldwide [1]. Recent findings by Buehring’s group have suggested that another virus, bovine leukemia virus (BLV) – which is highly prevalent in cows worldwide [2] – might be linked to human breast cancer [3–5]. In a study of 218 women from four states in the USA, Buehring’s group showed that the BLV positivity in women with breast cancer (67/114) is significantly higher than that in women without breast cancer (30/104) [4].