Editor—The use of hair as a biopsy tissue has been considered for some time. For instance, in the case of breast cancer, raised zinc levels in head hair have been reported.1 Besides, x ray diffraction patterns of hair are rich and have attracted much attention for 70 years.2 However, its potential use as a diagnostic indicator of disease was only suggested a short time ago.3 Most recently, James et al 4 reported that x ray diffraction of hair taken from women diagnosed with breast cancer (and those at high risk by virtue of a provenBRCA1/BRCA2mutation) showed a diffuse ring. They claimed a 100% correlation with the disease, advocating the use of pubic hair as a simple non-invasive screening method for breast cancer. The use of pubic hair was suggested in view of possible damage to the head hair from cosmetic treatments. Despite this note of caution, the study of James et al 4 was based on 12 pubic hair samples with only eight from cancer affected subjects. Here, we report a detailed double blind study from 109 women belonging to five clinically distinct groups as well …