AR, androgen receptor; ER-α, estrogen receptor alpha; ER-β, estrogen receptor beta; HPV, human papillomavirus; IHC, immunohistochemistry; FAK, focal adhesion kinase; OSCC, oral squamous cell carcinoma; PR, progesterone receptor; PCR: polymerase chain reaction. This evidence concerns the gene ESR1 and oral cavity squamous cell carcinoma.