PGR and breast cancer: All these findings suggest that HPV presence is related with higher aggressiveness of tumors, although it should be taken into account that some other authors have obtained contrary results, i.e. significantly higher percentage of HPV infection in tumors overexpressed oestrogen and/or progesterone receptors [10, 43] or lack of correlation between HPV infection and BC grade or immunophenotypes [25, 38, 40].