In addition, HNSCC cells (CAL 27 and SCC-9) expressed significantly more full-length Ki67 isoform (Ki67-F) and less exon 7-skipped isoform (Ki67-Δ7) than HaCaT cell, an immortalized and non-tumorigenic human keratinocyte (Figure 2C). Here, MKI67 is linked to head and neck squamous cell carcinoma.