Upregulation of SFTPC gene expression is associated with disease progression and worse survival outcomes in human skin melanomas.

The surfactant protein-C (SFTPC) gene encodes a hydrophobic pulmonary surfactant protein essential for lung function and homeostasis. While primarily associated with lung diseases, emerging evidence suggests its potential involvement in human cancers. In addition, SFTPC expression was also found in human skin cells, however, its expression profile in cutaneous melanoma is unknown. In this study, we analyzed expression profiles of SFTP family genes including SFTPA1/2, SFTPB, SFTPC, and SFTPD in human skin melanoma tissues. Our analysis revealed that SFTPC expression was the predominant SFTP gene and was associated with disease progression, including tumor stage, Clark level, and Breslow depth. High levels of SFTPC expression in skin melanoma tissues were significantly associated with patient survival outcomes including overall and disease-specific survival. The associations were specifically dictated in aggressive tumors, suggesting a potential role of SFTPC expression in melanoma progression. Interestingly, SFTPC expression was negatively correlated with T-helper cell infiltration in skin melanoma tissues. Gene enrichment analysis also indicated that SFTPC expression was in parallel with elevated expressions of mitochondrial energy biosynthesis-related genes and reduced IgE/IgG-mediated immunity-related genes. In conclusion, SFTPC upregulation is associated with disease progression and patient survival outcomes, possibly through enhancing ATP overproduction and suppressing antitumor immunity.