Carcinoma ex pleomorphic adenoma: A diagnostic challenge on cytology

Touch imprint smear: A prerequisite to obtain better quality and "true" tumor RNA in breast tissues

BACKGROUND

RNA is the primary genetic material required for various molecular studies. RNA derived from breast tissue has low quality and quantity compared to that extracted from other tissues. Therefore, optimization of techniques for breast tissue RNA extraction is a challenging but essential requirement.

METHODS

RNA was extracted from 60 samples of breast cancer after dividing them into 2 groups. Each tissue was divided into 2 halves for RNA extraction and histopathology respectively. In group 2 RNA was extracted after taking touch imprints whereas group1 was not subjected to any such procedure. Concentration and purity of RNA was assessed by using spectrophotometer and 1% agarose gel followed by RT-PCR for 18 S rRNA and CCND1 gene.

RESULTS

Based on microscopic observations of imprints, group 2 samples were further subdivided into 2 subgroups. Group 2 A (n = 30) showing tumor in imprint smears were found to yield best concentration of pure RNA (1846.50 ng/µl and 1.92) as compared to group 2B (n = 15) with no malignancy in imprints (102.61 ng/µl and 1.53). The correlation of imprint smears with their corresponding H&E-stained slides further leads to grouping of each group in 2 groups. RT-PCR analyses showed better melting peaks and high relative expression of CCND1 in group 2 A.

CONCLUSION

Touch imprints may provide valuable information regarding presence or absence of tumor in tissue samples being used for extraction of genetic material. This approach can be used as easy, cheap and fast strategy to resolve the doubts associated with RNA being truly representative of the tumor.

Heterogeneity and versatility of the extracellular matrix during the transition from pleomorphic adenoma to carcinoma ex pleomorphic adenoma: cumulative findings from basic research and new insights

Pleomorphic adenoma (PA) is the most common salivary gland tumor, accounting for 50%-60% of these neoplasms. If untreated, 6.2% of PA may undergo malignant transformation to carcinoma ex-pleomorphic adenoma (CXPA). CXPA is a rare and aggressive malignant tumor, whose prevalence represents approximately 3%-6% of all salivary gland tumors. Although the pathogenesis of the PA-CXPA transition remains unclear, CXPA development requires the participation of cellular components and the tumor microenvironment for its progression. The extracellular matrix (ECM) comprises a heterogeneous and versatile network of macromolecules synthesized and secreted by embryonic cells. In the PA-CXPA sequence, ECM is formed by a variety of components including collagen, elastin, fibronectin, laminins, glycosaminoglycans, proteoglycans, and other glycoproteins, mainly secreted by epithelial cells, myoepithelial cells, cancer-associated fibroblasts, immune cells, and endothelial cells. Like in other tumors including breast cancer, ECM changes play an important role in the PA-CXPA sequence. This review summarizes what is currently known about the role of ECM during CXPA development.

Molecular and Cellular Modelling of Salivary Gland Tumors Open New Landscapes in Diagnosis and Treatment

Salivary gland tumors are neoplasms affecting the major and minor salivary glands of the oral cavity. Their complex pathological appearance and overlapping morphological features between subtypes, pose major challenges in the identification, classification, and staging of the tumor. Recently developed techniques of three-dimensional culture and organotypic modelling provide useful platforms for the clinical and biological characterization of these malignancies. Additionally, new advances in genetic and molecular screenings allow precise diagnosis and monitoring of tumor progression. Finally, novel therapeutic tools with increased efficiency and accuracy are emerging. In this review, we summarize the most common salivary gland neoplasms and provide an overview of the state-of-the-art tools to model, diagnose, and treat salivary gland tumors.

Gene and immunohistochemical expression of HIF-1α, GLUT-1, FASN, and adipophilin in carcinoma ex pleomorphic adenoma development

OBJECTIVE

To analyze the gene and immunohistochemical expression of HIF-1α, GLUT-1, FASN, and adipophilin in normal salivary gland (NSG), pleomorphic adenoma (PA), and carcinoma ex pleomorphic adenoma (CXPA) samples.

MATERIAL AND METHODS

The gene expression was investigated by the real-time PCR (qRT-PCR) method in 9 samples of frozen tissues of normal salivary gland, 13 PA, and 10 CXPA. We validated the reactions by immunohistochemistry on 20 samples from NSG, 85 PA, and 44 CXPA.

RESULTS

Our results showed that there was no statistically significant difference in HIF-1α gene and immunohistochemistry expression among the tissues studied while FASN gene and immunohistochemistry expression increased along the carcinogenesis of the PA. GLUT-1 was significantly more expressed in tumor tissues (PA and CXPA), although protein is mainly expressed in transformed cells than in PA and NSG. In contrast, adipophilin was significantly more expressed in NSG while the expression of the protein increased in PA and CXPA.

CONCLUSIONS

In summary, the data presented here suggest that neoplastic cells reprogram the expression of GLUT-1 and adipophilin to adapt to the tumor microenvironment and reinforce, through immunohistochemical results, a possible transcriptional and post-translational regulatory mechanisms that act on the expression of these genes.

Immunohistochemical features of carcinoma ex pleomorphic adenoma and pleomorphic adenoma in the lacrimal gland

AIM

To investigate C-myc, Ki-67, pan-cytokeratin, and vimentin immunohistochemical features of carcinoma ex pleomorphic adenoma (Ca-ex-PA) and pleomorphic adenoma (PA) in the lacrimal gland in order to find some clues in the differential diagnosis between them.

METHODS

We reviewed microscopic slides and clinical records of 64 cases of PA and 15 cases of Ca-ex-PA in the lacrimal gland. Immunohistochemical antibodies for C-myc, Ki-67, pan-cytokeratin, and vimentin were employed.

RESULTS

Median age of PA was 43.2y (from 21 to 75). The 35 patients (54.7%) were male and 29 patients (45.3%) were female. For the PAs, the average positivity of C-myc was 4.6%; the average proliferation index of Ki-67 was 3.2%; pan-cytokeratin was positive in ductal cells, and vimentin was positive in myoepithelial cells. Median age of Ca-ex-PA was 54.3y (from 26 to 76). There were 7 male patients (46.7%) and 8 female patients (53.3%). Among 15 Ca-ex-PAs, there were 6 myoepithelial carcinomas, 4 adenocarcinomas, 3 epithelial-myoepithelial carcinomas, and 2 squamous cell carcinomas. For the Ca-ex-PAs, the average positivity of C-myc was 36.4%; the average proliferation index of Ki-67 was 29.2%; pan-cytokeratin was positive in all cases, and vimentin was positive in myoepithelial carcinomas.

CONCLUSION

PA has a lower positivity of C-myc and Ki-67, while Ca-ex-PA had a higher positivity of these two biomarkers. These four biomarkers as a set could provide valuable clues in the differential diagnosis between Ca-ex-PA and PA. Our results indicate that the activation of C-myc could play an important role in the pathogenesis of Ca-ex-PA and PA.