A molecular expression signature distinguishing follicular lesions in thyroid carcinoma using preamplification RT-PCR in archival samples.

Follicular variant of papillary thyroid carcinoma is a lesion that frequently causes difficulties from a diagnostic perspective in the laboratory. The purpose of this study was to interrogate a cohort of archival thyroid lesions using gene expression analysis of a panel of markers proposed to have utility as adjunctive markers in the diagnosis of thyroid neoplasia and follicular variant of papillary thyroid carcinoma in particular. Laser Capture Microdissection was used to procure pure cell populations for extraction. In addition a novel, multiplex preamplification technique was used to facilitate analysis of multiple targets. The panel comprised: HLA-DMA, HLA-DBQ1, CD74, CSNK1G2, IRF3, KRAS2, LYN, MT1K, MT1X, RAB23, TGFB1 and TOP2A, with CDKN1B as an endogenous control. Expression profiles for each target were generated using TaqMan Real-Time PCR. HLA-DMA, HLA-DQB1, MT1X, CSNK1G2 and RAB23 were found to be differentially expressed (P<0.05) when comparing follicular adenoma and follicular variant of papillary thyroid carcinoma. Comparison of follicular adenoma and follicular thyroid carcinoma groups showed significant differential expression for MT1K, MT1X and RAB23 (P<0.05). Comparison of the papillary thyroid carcinoma group (classic and follicular variants) and the follicular adenoma group showed differential expression for CSNK1G2, HLA-DQB1, MT1X and RAB23 (P<0.05). Finally, KRAS2 was found to be differentially expressed (P<0.05) when comparing the papillary thyroid carcinoma and follicular thyroid carcinoma groups. This panel of molecular targets discriminates between follicular adenoma, papillary thyroid carcinoma, follicular variant of papillary thyroid carcinoma and follicular thyroid carcinoma by their expression repertoires. It may have utility for broader use in the setting of fine-needle aspiration cytology and could improve the definitive diagnosis of certain categories of thyroid malignancy

Altered eIF6 and Dicer expression is associated with clinicopathological features in ovarian serous carcinoma patients.

MicroRNAs are a group of small non-coding RNAs approximately 22 nucleotides in length. Recent work has shown differential expression of mature microRNAs in human cancers. Production and function of microRNAs require coordinated processing by proteins of the microRNA machinery. Dicer and Drosha (RNase III endonucleases) are essential components of the microRNA machinery. Recently, the ribosome anti-association factor eIF6 has also been found to have a role in microRNA-mediated post-transcriptional silencing. We characterized the alterations in the expression of genes encoding proteins of microRNA machinery in ovarian serous carcinoma. Protein expression of eIF6 and Dicer was quantified in a tissue microarray of 66 ovarian serous carcinomas. Dicer, Drosha and eIF6 mRNA expression was analysed using quantitative reverse transcription-PCR on an independent set of 50 formalin-fixed, paraffin-embedded ovarian serous carcinoma samples. Expression profiles of eIF6 and Dicer were correlated with clinicopathological and patient survival data. We provide definitive evidence that eIF6 and Dicer are both upregulated in a significant proportion of ovarian serous carcinomas and are associated with specific clinicopathological features, most notably low eIF6 expression being associated with reduced disease-free survival. The status of eIF6 and proteins of the microRNA machinery may help predict toxicity and susceptibility to future interfering RNA-based therapy

Potentially important microRNA cluster on chromosome 17p13.1 in primary peritoneal carcinoma.

MicroRNAs are a group of small non-coding RNAs approximately 22 nucleotides in length. Recent work has shown differential expression of mature microRNAs in human cancers. We characterized the alteration in expression of a select group of microRNAs in primary peritoneal carcinoma relative to matched cases of ovarian serous carcinoma. MicroRNA expression was analysed using semi-quantitative stem-loop RT-PCR on a set of 34 formalin-fixed paraffin-embedded samples. Protein expression of p53 and bcl-2 was quantified in the corresponding tissue microarray. We provide definitive evidence that there is downregulation of a select group of microRNAs in tumours meeting Gynaecological Oncology Group criteria for primary peritoneal carcinoma relative to ovarian serous carcinoma. Specifically, we show decreased p53 expression and downregulation of miR-195 and miR-497 from the microRNA cluster site at chromosome 17p13.1 in primary peritoneal carcinoma relative to ovarian serous carcinoma. miR-195 and miR-497 may have potential roles as tumour-suppressor genes in primary peritoneal tumourigenesis