p63 expression in salivary gland tumors:: Role of ΔNp73L in neoplastic transformation

To illustrate the role of p63 and its truncated variants in salivary gland tumors, 23 consecutive tumors and 6 normal salivary glands were Studied immunohistochemically with anti-p63 antibody and by reverse transcriptase (RT) and nested polymerase chain reaction (PCR) to detect p63 isoform expression. Normal salivary glands: p63 antibody-stained basal and myoepithelial cells; by RT and nested PCR, the 2 main isoforms were present, whereas Delta Np73L was absent. Tumors: p63 antibody was positive in the following: Warthin tumor (WT) (3/3), oncocytoma (OC) (1/1), pleomorphic adenoma (PA) (7/7), polymorphous-low-grade adenocarcinoma (PLGA) (3/3), adenoid-cystic carcinoma (ADCC)(3/4), epithelial-myoepithelial-cell carcinoma (EMC) (1/1), and myoepithelial-cell carcinoma (MCC) (1/1). By RT and nested PCR all tumors expressed p63 irrespective of their morphologic differentiation. The Delta Np73L isoform was present in tumoral tissue but absent in normal salivary gland. These data suggest that p63, particularly its splice variant Delta Np73L, is involved in the neoplastic transformation of salivary glands.