Cyclin A expression and its diagnostic value in pleomorphic adenoma and carcinoma expleomorphic adenoma of the parotid gland

New diagnostic markers in salivary gland tumors

Parotid gland tumors are a rare and heterogeneous entity. Molecular markers are sparse. The aim of the study was to identify new diagnostic markers in benign and malignant salivary tumors. A tissue microarray was constructed with 158 tumor samples. Expression of 21 tumor antigens involved in tumor cell survival and known for prognostic potential was assessed immunohistochemically in all parotid gland samples. CEA, Cox-1, Cox-2, Sigma, beta-Catenin, WISP-1 and PDGF-beta were differently regulated in benign and malignant parotid tumors. Subsequently, these seven proteins entered the step-wise logistic regression analysis. As a second step, we defined a score for differentiating benign versus malignant parotid lesions: 4*CEA+15*Cox-1+4*Cox-2+4*Sigma+3*PDGF-beta+10*beta-Catenin+14*Wisp1. Sensitivity and specificity of 94 and 83% were reached. Besides routine hematoxylin and eosin staining, definition of new diagnostic markers and subsequently a new diagnostic score are an attempt to create an additional tool for the diagnosis of parotid gland tumors.

Lysine-specific demethylase 1 (LSD1) is highly expressed in ER-negative breast cancers and a biomarker predicting aggressive biology

Breast carcinogenesis is a multistep process involving both genetic and epigenetic changes. Since epigenetic changes like histone modifications are potentially reversible processes, much effort has been directed toward understanding this mechanism with the goal of finding novel therapies as well as more refined diagnostic and prognostic tools in breast cancer. Lysine-specific demethylase 1 (LSD1) plays a key role in the regulation of gene expression by removing the methyl groups from methylated lysine 4 of histone H3 and lysine 9 of histone H3. LSD1 is essential for mammalian development and involved in many biological processes. Considering recent evidence that LSD1 is involved in carcinogenesis, we investigated the role of LSD1 in breast cancer. Therefore, we developed an enzyme-linked immunosorbent assay to determine LSD1 protein levels in tissue specimens of breast cancer and measured very high LSD1 levels in estrogen receptor (ER)-negative tumors. Pharmacological LSD1 inhibition resulted in growth inhibition of breast cancer cells. Knockdown of LSD1 using small interfering RNA approach induced regulation of several proliferation-associated genes like p21, ERBB2 and CCNA2. Additionally, we found that LSD1 is recruited to the promoters of these genes. In summary, our data indicate that LSD1 may provide a predictive marker for aggressive biology and a novel attractive therapeutic target for treatment of ER-negative breast cancers.

Overexpression of EGFR and absence of C-KIT expression correlate with poor prognosis in salivary gland carcinomas

AIMS

To evaluate the prognostic impact of expression of receptor tyrosine kinases epidermal growth factor receptor (EGFR), HER2, and C-KIT in relation to established clinicopathological parameters in salivary gland carcinomas.

METHODS AND RESULTS

Immunohistochemistry for EGFR, HER2, C-KIT and the proliferation marker Ki67 was performed in 101 cases of salivary gland carcinoma and related to long-term clinical follow-up. Immunopositivity of C-KIT was common in adenoid cystic carcinoma (92%). Lack of C-KIT expression occurred in salivary duct carcinoma (P < 0.001) and was associated with high-grade tumours (P = 0.002), positive lymph nodes (P = 0.002) and high expression of Ki67 (P = 0.001). HER2 was typically expressed in salivary duct carcinomas (83%), but was not associated with any other parameter. EGFR overexpression occurred independently of histological type and clinical parameters. On univariate survival analysis, overexpression of EGFR (P = 0.011) and lack of C-KIT (P = 0.014) were associated with worse prognosis, whereas HER2 was of no prognostic significance. On multivariate analysis, the strongest negative predictor of survival was high proliferative activity measured by Ki67 (P = 0.002), followed by presence of residual tumour (P = 0.006), overexpression of EGFR (P = 0.026) and advanced tumour stage (P = 0.041).

CONCLUSIONS

The expression of receptor tyrosine kinases confers additional prognostic impact on disease-specific survival. EGFR overexpression is an independent negative prognostic factor.

Cyclin D1 and p16 expression in pleomorphic adenoma and carcinoma ex pleomorphic adenoma of the parotid gland

AIMS

To compare cyclin D1 and p16(ink4) (p16) expression in normal tissue, pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA) of the parotid gland.

METHODS AND RESULTS

Immunohistochemistry was used to examine cyclin D1 and p16 expression in 43 parotid tumours (29 PAs and 14 CXPAs). Cyclin D1 and p16 were both significantly more likely to be expressed in the neoplastic than in the normal epithelial and stromal components of PA and CXPA (P < 0.001 and P < 0.005, respectively). Cyclin D1 was more likely to be expressed in the malignant components of CXPA than in the benign components of PA (50% versus 31% and 31%, respectively), but the trend was not statistically significant. There was no evidence of this association for p16 (corresponding positivity rates 69% versus 81% and 52%).

CONCLUSIONS

Our findings provide preliminary evidence of roles for cyclin D1 and p16 in the development of PA and for cyclin D1 in the progression of PA to CXPA.