Is HPV a Culprit For Breast Carcinoma? A Retrospective Study

Abstract

The role of viruses in most common cancers is undoubtedly important, yet highly underestimated. Human Papilloma Virus (HPV) has been implicated with 99.7% of cervical cancers and its oncogenic mechanism has been clearly identified. The association of cervical cancer with 90% of triple negative breast cancer (TNBC) cases in African countries creates an intriguing possibility of HPV being a candidate oncovirus for breast cancer. In fact, numerous recent tissue studies conducted throughout the world detected HPV DNA in breast cancer tissues of patients with cervical cancer, while high‐risk HPV types (16, 18, 33) were present in invasive ductal carcinomas. 5,6 Prevalence of HPV varied from 4% in Mexican to 86% in American women. The virus was noted to be present in tumor tissue only, with the exception of one study, which identified lower concentration of HPV in normal tissue. 7 Although substantial evidence exists supporting involvement of HPV in breast cancer, no clinical studies have been conducted to elucidate this relationship. The goal of our retrospective chart review was to examine the association of breast cancer and HPV‐related cervical dysplasia in a cohort of women in urban setting. 15% (39/260) had abnormal Pap‐smear, while 8% (16/198) were HPVpositive. No statistically significant difference of Pap‐smear abnormality or of HPV positivity were detected among the groups in all categories. However, we noticed that non‐luminal breast cancers, double negative and triple negative (DN and TN), have higher rate of HPV positivity: 13.3% non‐luminal vs. 6.3% of luminal breast cancers, 12.5% DN breast cancers and 11.5% of TN vs. 6.4% of luminal A and 6.3% of luminal B. This creates an intriguing possibility that HPV might be associated with more than 50% increase of incidence rates of non‐luminal breast cancers, suggesting a need for larger scale studies to confirm this association.