The miRNAome of Opisthorchis viverrini induced intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC) is an aggressive cancer, arising in the biliary ducts that extend into the liver. The highest incidence of ICC occurs in Southeast Asia, particularly in the Mekong River Basin countries of Thailand, Laos, Cambodia, and Vietnam, where it is strongly associated with chronic infection by the food-borne liver fluke Opisthorchis viverrini (OV), one of only three eukaryote pathogens considered Group one carcinogens. Intrahepatic cholangiocarcinoma is usually diagnosed at an advanced stage, with a poor prognosis and survival often less than 24 months. Hence, biomarkers that enable the early detection of ICC would be desirable and have a potentially important impact on the public health in the resource-poor regions where this cancer is most prevalent. As microRNAs (miRNAs) remain well preserved after formalin fixation, there is much interest in developing them as biomarkers that can be investigated using tumor biopsy samples preserved in formalin fixed paraffin embedded (FFPE) tumor blocks. Recently, we reported the first comprehensive profiling of tissue-based miRNA expression using FFPE from the three most common subtypes of OV-induced ICC tumors: moderately differentiated ICC, papillary ICC, and well-differentiated ICC. We observed that each subtype of OV-induced ICC exhibited a distinct miRNA profile, which suggested the involvement of specific sets of miRNAs in the progression of this cancer. In addition, non-tumor tissue adjacent to ICC tumor tissue on the same FFPE block shared a similar miRNA dysregulation profile with the tumor tissue than with normal (non-tumor) liver tissue (individuals without ICC or OV infection). Herein, we provide a detailed description of the microarray analysis procedures used to derive these findings.

Spindle cell foci in the thyroid gland: an immunohistochemical analysis.

Spindle cell proliferations of the thyroid gland are uncommon lesions that encompass a wide spectrum of reactive, hyperplastic, and neoplastic processes. Spindle cells may occur in subsets of papillary carcinomas and follicular adenomas where they are thought to represent metaplastic foci. The goals of the present study are to further characterize the metaplastic nature of spindle cell foci of the thyroid (SCFT), to define their immunohistochemical profiles and to review their differential diagnoses. The study group included: multinodular goiter (2), follicular adenoma (2), and minimally invasive follicular carcinoma (2). SCFTs were composed of elongate cells with thin or slightly plump nuclei with finely granular chromatin and inconspicuous nucleoli. Rare mitotic figures were present but there was no necrosis or inflammation. All cases were positive for thyroglobulin, thyroid transcription factor (TTF)-1, and TTF-2. TTF-1 and TTF-2 had a characteristic nuclear localization although the intensity of staining for TTF-1 was consistently greater than that of TTF-2. Each of the 6 cases was positive for vimentin whereas 5 of the 6 cases were positive for broad-spectrum cytokeratins. None of the cases was positive for high molecular weight cytokeratin, cytokeratin-19, smooth muscle actin, desmin, calcitonin, chromogranin, or synaptophysin. The proliferative rate was less than 1% in all cases. Staining for TTF-1 and TTF-2 provided high specificity for identification of SCFT since these markers were not subject to the same diffusion artifact inherent in thyroglobulin-stained sections. The results of this study further support the hypothesis that SCFT result from metaplastic transformation of follicular cells.

Differential expression of high-affinity melatonin receptors (MT1) in normal and malignant human breast tissue.

Melatonin is a pineal hormone that strongly inhibits the growth of breast cancer cells in vitro and in vivo. We report thefirst use of immunohistochemical analysis to determine the distribution of the high-affinity melatonin receptor subtype, MTI, in human breast tissue, the hypothalamic suprachiasmatic nucleus, and skin. The MT1 antibody, which is specific for the cytoplasmic portion of the receptor, produced cytoplasmic staining in normal-appearing breast epithelial cells and ductal carcinoma cells; stromal cells, myoepithelial cells, and adipocytes were nonreactive. The majority of nonneoplastic samples (13/19 [68%]) were negative to weakly positive, while moderate to strong reactivity was seen in most cancer samples (49/65 [75%]). Thus, although MT1 receptors were detectable in normal and malignant breast epithelium, high receptor levels occurred more frequently in tumor cells (P < .001), and tumors with moderate or strong reactivity were more likely to be high nuclear grade (P < .045). These findings may have implications for the use of melatonin in breast cancer therapy.