Basal Cell Carcinoma: A Digital Study of Immunohistochemical BCL2, P53 and CD138 Expression in Low- and High-Risk Types

IntroductionBasal cell carcinoma (BCC) is the leading cancer in Caucasians globally. Certain histological types of BCC are defined as high-risk for recurrence by the World Health Organisation (WHO). Identifying biological differences, such as protein expression, between histological types could result in druggable targets and improve future management, potentially offsetting rising costs in the health sector due to an increase in the global incidence of aggressive BCC.MethodsA laboratory-based, immunohistochemical study was undertaken at our institution. BCL2, P53 and CD138 antibodies were applied to formalin-fixed, paraffin-embedded tissue from low-risk and high-risk BCC types; followed by whole slide scanning and digital interpretation using QuPath software. Staining intensity, proportion and scores were assessed with the addition of BCL2 labelling and CD138 location. Statistical analyses were performed using STATA and R. A p value < 0.05 was considered statistically significant.ResultsOf 121 BCCs examined, 78 were low- and 43 high-risk. BCL2, P53 and CD138 tumoural expression in BCC were 78%, 91% and 100%, respectively. BCL2 staining was predominantly weak and focal while P53 and CD138 were diffuse. Significantly decreased tumoural BCL2 labelling (p = 0.04) and CD138 scores (p = 0.0035) were observed in high-risk BCCs. Conversely, significantly increased peritumoural stromal CD138 expression was observed in this category (p < 0.0001). There was no significant difference in P53 expression between the two categories.ConclusionThe identification of decreased BCL2 labelling in high-risk BCC highlights an important area for further research to evaluate the effect BCL2 downregulation has on non-surgical therapeutic options in aggressive BCC.