HPV infection and triple-negative breast cancers: an Italian case-control study

BACKGROUND: Breast cancer is one of the most important neoplasia among women. To reduce its incidence and mortality impact it would be desirable to early identify risk factors associated with its development. It was recently suggested that biological agents could be the etiological cause, particularly Human Papilloma Virus (HPV). No specific relationship with different breast cancer types has been demonstrated until now. In particular, the triple-negative breast cancer (TNBC), characterized by a receptor negative pattern (ER/PgR/HER2–negative) and poor prognosis, can represent one of the most relevant clinical and public health priority in terms of observational research. FINDINGS: Aim of the study was to evaluate the HPV-positivity prevalence in two breast cancer series (TNBC vs. non-TNBC) in Northern Sardinia, Italy. The sample size of each group was represented by 40 formalin-fixed and paraffin-embedded specimens. The mean age was 60.3 years. The majority of the cancers were ductal (84%). The grading distribution was different: G2 was the most prevalent grade in the non-TNBC series, whereas G3 was the most frequent in the TNBC series (70% and 72%, respectively). Six biological samples were HPV-positive (7.5%): the positivity was assessed only in the TNBC group (15%; p-value: 0.026). The isolated genotypes were: 16, 31, 45, 52, 6, and 66. Only one co-infection was found (i.e., HPV-6 and -66). CONCLUSIONS: The prevalence of HPV-positivity in TNBC specimens was 15%. On the basis of its carcinogenetic ability, an etiological role in the pathogenesis of the cancer could be supposed. This association should be confirmed with longitudinal studies to better assess the role of the HPV infection in TNBC and non-TNBC tumors.