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ABSTRACT Background Methods Results Conclusion Mucinous cells can be detected sporadically or may constitute the primary tumor component in salivary gland tumors, as observed in the intraductal papillary mucinous neoplasm (IPMN). This low‐grade tumor is composed of mucinous columnar cells organized into papillary cystic structures. The present study aimed to compare the mucous cells in IPMN with mucous cells present in mucoepidermoid carcinoma (MEC) and papillary cystadenoma (PC).Immunohistochemistry analysis was carried out to compare the mucous cells in IPMN with the sporadic mucous cells in MEC (n = 4) and PC (n = 3).The results indicated that IPMN cells were positive for CK7, CK18, DOG1, and NKX3.1 and negative for CK14, SMA, and p63. The mucous cells in both MEC and PC were positive for CK7 and negative for CK18, SMA, DOG1, and NKX3.1. The positive expression of CK14 and p63 revealed the presence of basal cells both in PC, cystic areas of MEC, and normal mucous salivary glands.The immunohistochemical profile of IPMN closely resembles that of the mucous cells of the minor salivary glands yet differs from the mucous cells observed in MEC and PCX. This suggests that IPMN is probably derived from the transformation of secretory cells of the minor mucous salivary gland and has no rimming/basal cells. For this reason, we propose that this tumor is designated as mucous acinic cell carcinoma. [ABSTRACT FROM AUTHOR]

Salivary gland tumors are a highly heterogeneous group of lesions with diverse microscopic appearances and variable clinical behavior. The use of clinical and histological parameters to predict patient prognosis and survival rates has been of limited utility, and the search for new biomarkers that could not only aid in a better understanding of their pathogenesis but also be reliable auxiliaries for prognostic determination and useful diagnostic tools has been performed in the last decades with very exciting results. Hence, gene rearrangements such as CRTC1-MAML2 in mucoepidermoid carcinomas have shown excellent specificity, and more than that, it has been strongly correlated with low-grade tumors and consequently with an increased survival rate and better prognosis of patients affected by neoplasms carrying this translocation. Moreover, MYB-NFIB and EWSR1-ATF1 gene fusions were shown to be specifically found in cases of adenoid cystic carcinomas and hyalinizing clear cell carcinomas, respectively, in the context of salivary gland tumors, becoming reliable diagnostic tools for these entities and potential therapeutic targets for future therapeutic protocols. Finally, the identification of ETV6-NTRK3 in cases previously diagnosed as uncommon acinic cell carcinomas, cystadenocarcinomas, and adenocarcinomas not otherwise specified led to the characterization of a completely new and now widely accepted entity, including, therefore, mammary analogue secretory carcinoma in the list of well-recognized salivary gland carcinomas. Thus, further molecular investigations of salivary gland tumors are warranted, and the recognition of other genetic abnormalities can lead to the acknowledgment of new entities and the acquirement of reliable biomarkers. [ABSTRACT FROM AUTHOR]

Background Claudins are transmembrane proteins of tight junctions emerging as targets for diagnosis, prediction of prognosis, disease recurrence, and metastasis. Our goal was to evaluate expression of claudin-4 in the most common benign and malignant salivary gland neoplasms. Methods Claudin-4 gene levels and protein expression were determined by real-time polymerase chain reaction (PCR), and immunohistochemistry in a total of 30 specimens containing normal salivary tissue, pleomorphic adenoma, Warthin's tumor, mucoepidermoid carcinoma, and adenoid cystic carcinoma. Results We identified down-regulation of claudin-4 gene levels and protein expression from normal control to benign salivary gland neoplasms and reached their lowest values in the malignant salivary gland neoplasms. Conclusions Low claudin-4 expression could be considered as a sign of increasing cellular disorientation and invasion of salivary gland tumors. [ABSTRACT FROM AUTHOR]

J Oral Pathol Med (2012) 41: 207-213 Background: Adenoid cystic carcinoma (AdCC) is a common malignant salivary gland tumor. AdCC is histologically characterized as having cribriform, tubular and solid patterns, and production of excess extracellular matrix (ECM). Cancer stem cells (CSCs) are defined cells within a tumor that possess the capacity to self-renew and to induce the heterogeneous lineages of cancer cells that comprise the tumor. Methods: To examine the morphogenetic relationship between CSCs and the growth patterns in AdCC, we employed formalin-fixed and paraffin-embedded 26 cases of AdCC and immunohistochemically clarified the distribution of CSCs using CD133 and CD44 antibodies. Results: CD133- or CD44-positive cancer stem (CS)-like cells were scattered in the pseudocyst-lining area of cribriform patterns having a Swiss cheese-like appearance. However, based on the further overproduction of ECM, CS-like cells accumulate in thin epithelial cords or trabecular arrangements. These CS-like cell aggregations are considered to form two cell-layered tubular patterns. Moreover, proliferation of outer cells in tubular patterns leads to cribriform patterns or solid patterns in the presence of excess ECM production or a lack of ECM overproduction, respectively. CS-like cells in AdCC were frequently located at the border areas adjacent to ECM, with exception of some cribriform and solid variants. Conclusion: It is suggested that CSCs included in CD133- or CD44-positive cells play an important role in morphogenesis of salivary AdCC, especially in transition among the histological growth patterns. ECM is well known as a component of the CSC microenvironment, and ECM may regulate morphogenesis of AdCC through the stimulation of CSCs. [ABSTRACT FROM AUTHOR]

Background: It is still controversial if atypical tumor cells scattered in salivary pleomorphic adenomas are precancerous and how carcinoma arises in pleomorphic adenomas.Methods: We studied clinicopathologically the frequency and variation of cellular atypia among tumor cells and examined the expression status of p53 gene products as well as proliferating cell nuclear antigen (PCNA) in 101 surgical materials of pleomorphic adenomas.Results: Histopathologically, atypical tumor cells were found in 51% of the cases examined. Their mode of distribution was classified into three groups: focal (six cases, 6%) which could be identified as focal carcinoma, measuring less than 1 mm in diameter; sporadic (15 cases, 15%) and singular (30 cases, 30%). These atypical cells were located mainly within sheet-like nests of tumor cells but not in chondroid or fibro-hyaline foci. Immunohistochemically, most of the atypical cells were positive for p53 gene products and PCNA.Conclusion: The results indicated that atypical cells with p53 protein accumulation in their nuclei could be regarded as cells in a precancerous state not yet forming an apparent carcinomatous nest. Some cell population with these atypical cells are likely to form focal carcinomas and then to an apparent form of carcinoma in pleomorphic adenoma. [ABSTRACT FROM AUTHOR]

Forty-three intraoral salivary gland tumors were studied to determine the value of the AgNOR technique in the assessment of these neoplasms. Well defined black dots were visible in the nucleii of all the specimens studied. The mean AgNOR count per nucleus for each tumor was calculated as follows: pleomorphic adenoma (n = 15) 1.52; Polymorphous low-grade adenocarcinoma (n = 12) 1.90; adenoid cystic carcinoma (n = 6) 2.92; mucoepidermoid carcinoma (n = 4) 1.93; carcinoma ex mixed tumor (n = 4) 2.05; undifferentiated carcinoma (n = 1) 3.13 and epithelial-myoepithelial carcinoma (n = 1) 2.23. The difference between the means of benign and malignant tumors (P less than 0.01) and polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma (P less than 0.01) were highly significant. The overlapping of the AgNOR count between various tumors prohibited the use of this technique as an absolute criterion in establishing a final diagnosis. It could however be used as a diagnostic aid in differentiating between salivary gland neoplasms. [ABSTRACT FROM AUTHOR]

We describe the case of a bilateral parotid mucosa-associated lymphoid tissue (MALT) lymphoma associated with 2 years history of Sjögren's syndrome (SS), which was linked to human herpes virus 8 (HHV-8) infection. Using polymerase chain reaction (PCR) assay HHV-8 sequences were detectable in the lymphoma tissue of both sides. Serologic testing of the patient revealed HHV-8 antibodies in enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). Immunohistologic staining with two antibodies against open reading frame (ORF) 26 and v-cyclin homologues of HHV-8 revealed positive staining of the salivary acinic cells whereas the lymphoma cells were negative. The potential influence of HHV-8 infection for MALT lymphoma development in this case and possible parallels to gastric MALT lymphoma are discussed. [ABSTRACT FROM AUTHOR]