MMP1 and head and neck squamous cell carcinoma: Since, CELF1 mRNA and protein levels are known to be decreased in normal versus tumor tissues, the pattern of expression observed for ESM1, KLF4, IL8, CCL20, IL24, CCNA1, TIMP4 and MMP1 mRNAs, suggest that CELF1 may be a regulator of these targets in HNSCC.