HCG18 and head and neck squamous cell carcinoma: Emerging evidence has demonstrated that long noncoding RNA (lncRNAs) play a vital role in the development of head and neck squamous cell carcinoma (HNSCC); however, the biological effects and underlying mechanisms of human leukocyte antigen complex group-18 HCG18 (HCG18) have not yet been reported in HNSCC.