HOXB13 and prostate cancer: HOXB13 is a homeobox transcription factor gene and a single rare variant G84E confers a significantly increased risk for prostate cancer97,98 The odds ratios for development of associated with this variant range from 2.9 (95% CI: 1.9–4.6) in the UK Genetic Prostate Cancer Study (UKGPCS) to 8.8 (95% CI: 4.9–15.7) among men with a family history in a Finnish study by Laitinen et al.99,100.