COL1A1 and oral cavity squamous cell carcinoma: Existing studies have shown that COL1A1 (encoded by the collagen type 1 alpha 1 gene) has some predicative value in tumor diagnosis and prognosis where it has been found to be upregulated and downregulated in oral squamous cell carcinoma and hepatocellular carcinoma respectively.[25–27] Another explanation for the observed collagen changes is the reversion of the atrophied adult thymus composed mostly of adipocytes and stroma.