Evaluation of the polymerase chain reaction-based T-cell receptor ß clonality test in the diagnosis of early mycosis fungoides.

BACKGROUND: T-cell receptor (TCR) clonality may help establish a diagnosis of mycosis fungoides (MF). Routine clonality analysis is performed by using a polymerase chain reaction TCR- gamma assay, yet with this method, 10% to 50% of T-cell lymphomas escape detection. TCR- beta gene rearrangement is an additional assay. Data about its efficacy are controversial. OBJECTIVE: To evaluate the role of TCR-ß assay in the diagnosis of early MF. METHODS: A retrospective study of 61 skin biopsies, 20 from patients with MF, 30 from patients suspected to have early MF, and 11 from patients with chronic inflammatory skin disease. RESULTS: Monoclonality was detected in 16 of 20 (80%) MF cases: 15 (75%) with TCR-ß and 12 (60%) with TCR-γ assay. Of the 30 suspected cases of early MF, 14 showed monoclonality with TCR-ß, and only 5 of 14 showed monoclonality with TCR-γ assay. None of the chronic inflammatory condition samples showed monoclonality. Therefore, TCR-ß clonality assay was more sensitive than TCR-γ in early MF (83% vs 43%; P = .002). LIMITATIONS: This was a retrospective, relatively small study. CONCLUSION: TCR-ß showed a higher sensitivity rate compared with TCR-γ in early-stage MF. The combined use of the TCR-ß and TCR-γ clonality tests can significantly improve the diagnosis rate of early-stage MF.

Giardia lamblia miRNAs as a new diagnostic tool for human giardiasis.

BACKGROUND: Giardia lamblia is a very common cause of gastrointestinal symptoms worldwide. There are several methods for the diagnosis of Giardia infection, however none are ideal. We aim to find a new, microRNA-based method that will improve the currently available diagnostic methods for giardiasis. METHODS: Deep-sequence profiling of Giardia small-RNA revealed that miR5 and miR6 are highly expressed in Giardia. These miRNAs were tested by qRT-PCR in duodenal biopsies of patients with giardiasis who were positive by microscopic pathological evaluation. The gastric biopsies of the same patients served as negative control tissues. Additionally, these miRNAs were evaluated in stool samples of patients with proven giardiasis. RESULTS: All histologically proven duodenal biopsies of patients with Giardia infection were positive for Giardia miR5, with a mean threshold cycle (Ct) of 23.7, as well as for Giardia DNA qPCR (16S-like gene, mean Ct 26.3). Gastric biopsies which were tested as a control all were negative. Stool evaluation of miR6 in patients with giardiasis showed 90% specificity but only 66% sensitivity, and a lower accuracy rate was obtained with miR5. CONCLUSION: Giardia miR5 testing in duodenal biopsies may be a new method for the diagnosis of giardiasis. It seems to be more sensitive when compared with testing for Giardia DNA by qPCR in duodenal biopsies. It will be important to investigate the contribution of routine Giardia miRNA testing in duodenal biopsies from patients with persistent abdominal symptoms.

MicroRNA expression differentiates between primary lung tumors and metastases to the lung.

For surgical pathologists, distinguishing whether a pulmonary neoplasm is primary or metastatic can be challenging, and current biomarkers do not always aid lung tumor classification. The tissue-associated expression of microRNA likely explains the remarkable finding that many tumors can be classified based solely on their microRNA expression signature. Here we show that microRNAs can serve as biomarkers for lung tumor classification. Using microRNA microarray data generated from 76 formalin-fixed, paraffin-embedded (FFPE) samples of either primary lung cancer or metastatic tumors to the lung, we have identified a set of microRNAs expressed differentially between these two groups. This set includes hsa-miR-182, which was most strongly over-expressed in the lung primary tumors, and hsa-miR-126, which was over-expressed in the metastatic tumors. The differential expression of this set of microRNAs was confirmed using qRT-PCR on a set of 54 samples. In light of our data, microRNA expression should be considered as a potential clinical biomarker for surgical pathologists faced with discerning the tumor type of an inscrutable lung neoplasm.