Humans ; Adenoma, Pleomorphic/genetics* ; Adenoma ; Salivary Gland Neoplasms/genetics* ; Adaptor Proteins, Signal Transducing

Pleomorphic adenoma (PA) is the most common benign tumour in the salivary gland and has high morphological complexity. However, the origin and intratumoral heterogeneity of PA are largely unknown. Here, we constructed a comprehensive atlas of PA at single-cell resolution and showed that PA exhibited five tumour subpopulations, three recapitulating the epithelial states of the normal parotid gland, and two PA-specific epithelial cell (PASE) populations unique to tumours. Then, six subgroups of PASE cells were identified, which varied in epithelium, bone, immune, metabolism, stemness and cell cycle signatures. Moreover, we revealed that CD36⁺ myoepithelial cells were the tumour-initiating cells (TICs) in PA, and were dominated by the PI3K-AKT pathway. Targeting the PI3K-AKT pathway significantly inhibited CD36⁺ myoepithelial cell-derived tumour spheres and the growth of PA organoids. Our results provide new insights into the diversity and origin of PA, offering an important clinical implication for targeting the PI3K-AKT signalling pathway in PA treatment.
Humans ; Adenoma, Pleomorphic/genetics* ; Phosphatidylinositol 3-Kinases ; Proto-Oncogene Proteins c-akt ; Transcriptome ; Myoepithelioma

OBJECTIVETo analyze the original mutated codon of p53 gene of salivary pleomorphic adenoma (SPA) and to evaluate the repair effects of wt-p53 on SPA cells.

METHODSFour cases of SPA were obtained from clinical fresh samples and SPA cells were separated and cultured, and then the cells were transduced by Ad-wt-p53. The cells and the corresponding tumor tissue DNA were extracted, PCR and single strand conformational polymorphism (SSCP) and DNA sequencing analysis were performed.

RESULTSPCR-SSCP analysis showed 3 out of 4 SPA with abnormal exon 8 and abnormal exon 6. DNA sequencing analysis showed that exon 6 point mutation was found at codon 203 (GTG-->GCG), poly-codon mutations were found in exon 8 at codon 272 (GTG-->GT square), 275 (TGT-->T square T), 276 (GCC--> square CC) and at codon 290 (CGC-->CGCC). After transduced by Ad-wt-p53, all of the mutated codons were repaired.

CONCLUSIONSp53 gene mutation involved many codons that occurred frequently in the tumorigenesis of SPA. Exogenous wt-p53 could compensate and repair all the mutated p53 codons of SPA cells. SPA cells transduced by Ad-wt-p53 showed the typical apoptosis.

Adenoma, Pleomorphic ; genetics ; DNA Repair ; Humans ; Mutation ; Polymorphism, Single-Stranded Conformational ; Salivary Gland Neoplasms ; genetics ; Transfection ; Tumor Cells, Cultured ; Tumor Suppressor Protein p53 ; genetics

OBJECTIVETo explore the diagnostic value of MYB protein expression for adenoid cystic carcinoma and its differential diagnosis from other salivary gland tumors, and to further investigate the status of MYB gene copy number.

METHODSMYB expression was studied by immunohistochemistry in 34 adenoid cystic carcinomas, 55 non-adenoid cystic carcinomas (other salivary gland tumors) including 10 pleomorphic adenomas, 10 basal cell adenomas, 10 epithelial-myoepithelial carcinomas, 9 basal cell adenocarcinomas, 8 mucoepidermoid carcinomas, 4 carcinoma in pleomorphic adenomas, and 4 polymorphous low-grade adenocarcinoma. MYB gene copy number status was detected by FISH in MYB protein-positive cases.

RESULTS82.4% (28/34) of adenoid cystic carcinomas were MYB protein-positive, compared with 9.1% (5/55) of non-adenoid cystic carcinomas, and the difference between the two groups was statistically significant (P < 0.01). 2/18 of adenoid cystic carcinomas had duplication of MYB gene by FISH, and all non-adenoid cystic carcinomas were negative although the difference was not statistically significant (P = 0.435).

CONCLUSIONSMYB protein expression is a useful diagnostic marker for adenoid cystic carcinomas in its separation from other salivary gland tumors. In addition, duplication of MYB gene is no a major mechanism for the MYB protein overexpression.

Adenoma ; Adenoma, Pleomorphic ; Biomarkers, Tumor ; genetics ; metabolism ; Carcinoma, Adenoid Cystic ; diagnosis ; genetics ; metabolism ; Carcinoma, Mucoepidermoid ; Diagnosis, Differential ; Gene Dosage ; Humans ; Immunohistochemistry ; Proteomics ; Proto-Oncogene Proteins c-myb ; genetics ; metabolism ; Salivary Gland Neoplasms

OBJECTIVETo study the expression of p16 and nm23 genes in salivary gland tumors and the relation of P16 and nm23 proteins with fumorigenesis of salivary gland tumors.

METHODSExpression of P16 and nm23 proteins was examined by SABC immunohistochemical method in 39 cases of paraffin blocks of normal salivary gland tissues and salivary gland tumors.

RESULTSP16 and nm23 protein positive staining were mainly found in the cytoplasm and cytoblast of all salivary gland tissues. Positive rate of P16 protein expression was 76.9% (10/13) and 40.9% (9/22) in benign and malignant salivary gland tumors, respectively. There was significant difference between P16 protein expression of benign and malignant tumors by chi 2 test (P < 0.05). mm23 protein positive staining was found in 84.6% (11/13) and 45.5% (10/22) of benign and malignant tumors respectively. The expression of nm23 protein in benign and malignant tumors was significantly different (P < 0.05). There was no correlation of the expression of P16 and nm23 in salivary gland tumors was found (P > 0.05).

CONCLUSIONp16 and nm23 genes may play an important role in different sides in salivary gland tumorigenesis and the reduce of the expression of p16 and nm23 genes may contribute to the generation of malignant salivary gland tumors.

Adenoma, Pleomorphic ; genetics ; metabolism ; Carcinoma, Mucoepidermoid ; genetics ; metabolism ; Cyclin-Dependent Kinase Inhibitor p16 ; biosynthesis ; genetics ; Humans ; Immunohistochemistry ; NM23 Nucleoside Diphosphate Kinases ; Nucleoside-Diphosphate Kinase ; Protein Biosynthesis ; Proteins ; genetics ; Salivary Gland Neoplasms ; genetics ; metabolism ; Salivary Glands ; metabolism