TP63 and head and neck squamous cell carcinoma: PTBP1 depletion strongly increases the abundance of TP63 γ exon and decreases levels of TP63β in HaCaT cells without affecting global TP63 (TP63_all) or TP63α mRNA levels (Fig. 6A and B) as we previously showed in HNSCC cell lines (Fig. 4D).