Differential expression of HER2, STAT3, SOX2, IFI16 and cell cycle markers during HPV-related head and neck carcinogenesis

The aim of this study was to analyze protein and gene expression of HER2 in 224 head and neck precancerous and malignant lesions by immunohistochemistry and FISH analysis. In parallel, expression of pStat3, Sox2, IFI16 and p16, Ki67 was evaluated. Immunohistochemical analysis was assessed on formalin-fixed paraffin-embedded (FFPE) tissue specimens. A combined method for HPV detection consisting of p16 immunostaining and two PCR probes was applied. HER2 gene status was evaluated by FISH analysis. HPV DNA was detected in 24% of cases with predominant HPV16 genotype. HPV-positive lesions had higher HER2, pStat3 and within carcinoma group, and higher IFI16 expression compared to the HPV-negative group (Fig. 1A-B-C). A strong positive correlation between Sox2 and proliferative activity was observed, whereas IFI16 expression displayed a negative relationship with Sox2 and Ki67 activity. The most striking result was higher pStat3 expression in HPV-positive lesions and its strong positive correlation with IFI16 expression. The presence of HPV may induce upregulation of HER2/neu, pStat3 and IFI16. High levels and a strong positive correlation between pStat3 and IFI16 suggest their synergistic pro-apoptotic effects in HPV-positive lesions.