The expression levels of 110 kDa NCL in the nucleus reduced but an 80 kDa NCL degradation fragment appeared in human salivary gland cells, human oral squamous cell carcinoma cells (SCC‐25), and human osteoblasts (Saos‐2 and MG63) when induced by okadaic acid (OA).7, 8. This evidence concerns the gene NUCLEOLIN and oral cavity squamous cell carcinoma.