Immunohistochemical Evaluation of S100, Alpha-Smooth Muscle Actin, Podoplanin, Matrix Metalloproteinase 13, and Human Epidermal Growth Factor Receptor 2neu Markers in Basal Cell Carcinoma Variants

Background Variants of basal cell carcinoma (BCC) appear to behave biologically differently. Several histological patterns impact the concept of low-risk (indolent) and high-risk (aggressive) types in the head and neck. This study aims to assess the biological behavior of BCC variants by immunohistochemical expression of S100, alpha-smooth muscle actin (α-SMA), podoplanin, matrix metalloproteinase 13 (MMP-13), and human epidermal growth factor receptor 2 (HER2)neu biomarkers. Methodology A total of 65 paraffin-embedded tissue blocks of BCC of the head and neck were retrieved from the collections of the Histopathology Department of the Medical City Teaching Complex and the Ghazi Al-Harerri Hospital at the University of Baghdad’s College of Dentistry, spanning the years 2015 through 2021. S100, α-SMA, podoplanin, MMP-13, and HER2neu biomarkers were used to perform immunohistochemical analysis (Abcam). Results This study noticed different expressions of S100, α-SMA, podoplanin, MMP-13, and HER2neu between different variants. There was no immunohistochemical expression in perineural invasion with all cases of BCC variants. The highest expression was seen in HER2neu, MMP-13, and α-SMA with aggressive histological patterns. There was no podoplanin lymphatic vessel density immunoexpressing in all variants, while tumoral podoplanin showed a significant difference in all variants. HER2neu was correlated with all other biomarkers. Conclusions HER2neu, MMP-13, and α-SMA biomarkers can be used as diagnostic markers to predict the aggressive biological behavior of BCC tumors.