Correlation of MMP-9 (Matrix Metalloproteinase 9) and SMA (Smooth Muscle Actin) expression with Basal Cell Carcinoma’s risk of recurrence

Basal Cell Carcinoma (BCC) is the most common cancer in many countries, with its incidence steadily rising. Data from the Indonesian Pathologists Association show that among 1,530 skin cancer cases, BCC was the most frequent (39.93%), followed by Squamous Cell Carcinoma (23%) and Malignant Melanoma (7.9%). According to the 2018 WHO classification, BCC is divided into Low-Risk and High-Risk groups based on the risk of recurrence. BCC invades surrounding tissues through extracellular matrix degradation and enhanced cell motility, driven by the expression of MMP-9 (Matrix Metalloproteinase 9) and SMA (Smooth Muscle Actin). This study aims to evaluate the expression of MMP-9 and SMA in BCC using immunohistochemistry and analyze their correlation with the risk of recurrence. A total of 40 paraffin blocks from BCC patients diagnosed between 2019 and 2021 at Dr. Saiful Anwar General Hospital in Malang, Indonesia, were sampled. The blocks were sectioned, stained with MMP-9 and SMA antibodies, and examined for positive expression indicated by brown staining in the cytoplasm of tumor cell and peritumoral stroma. Spearman correlation showed r = 0.811 for MMP-9 and r = 0.857 for SMA (p < 0.05, CI: 95%), indicating a significant relationship between these markers and the risk of recurrence. Higher MMP-9 and SMA expression corresponded to a higher risk of BCC recurrence, suggesting their potential as prognostic biomarkers. However, further research is needed to assess recurrence risk more accurately and determine the most appropriate therapy.