CTLA4 and cancer: Thomas et al. [ 25] examined various mechanisms and found that cancer cells use diverse approaches to promote the JAK/STAT pathway; for head and neck SCC, tumor cells express CTLA4,which phosphorylates the STAT3 gene; thus, CTLA4 can positively correlate with STAT3, which is similar to our results.Studies show that increased expression of CTLA4 is associated with several cancers.