SMN1 and cancer: Notably, an RNA-sequencing dataset of 501 whole tumors from patient lung squamous cell carcinomas showed a correlation between low MUT, MCEE, MMAA and MMAB levels (indicating high MMA) and high expression of cancer-associated fibroblast markers ACTA1 (encoding for SMA) and FAP (Fig. s1d), suggesting that human tumors with greater levels of MMA do indeed harbor a great proportion of CAFs.