MiRNA Differentiates Squamous and Nonsquamous Forms of Lung Cancer

Effective treatment of non-small-cell lung cancer (NSCLC) requires accurate diagnosis to establish whether the tumor is squamous or nonsquamous, a task now made easier with a commercially available microRNA-based assay.

In treating patients with NSCLC, identification of the squamous sub-type has significant clinical implications. Squamous lung cancer carries increased risk of severe or fatal bleeding for certain targeted biological therapies, including bevacizumab and other drugs under development. Other approved therapies, such as pemetrexed are indicated for nonsquamous NSCLC only.

A diagnostic kit based on microRNA (miRNA) technology capable of differentiating the squamous and nonsquamous forms of NSCLC was recently evaluated by investigators at Johns Hopkins University (Baltimore, MD, USA). In their study, 102 resected NSCLC samples were classified using histopathology "gold standard" methods as well as a panel of immunohistochemical stains. Results were then compared to those obtained with the Rosetta Genomics Laboratories (Rehovot, Israel) miRview squamous mi-RNA-based test. Additionally, preoperative samples from 21 cases originally diagnosed as poorly differentiated NSCLC were analyzed with miRview squamous, and compared with the classification obtained following the patient's surgery.

Results published in the January 12, 2010, online edition of the journal Clinical Cancer Research revealed that there was 100% concordance between the diagnoses established by the "gold standard" and immunochemical methods and miRview squamous for the resected NSCLC samples. The kit's miRNA profiling technology also correctly classified 20 of the 21 (95%) preoperative biopsy specimens.

The miRview assay is based on hsa-miR-205, a miRNA that is highly expressed in lung squamous cell carcinomas (SqCC) but not in lung adenocarcinomas. The advantage of using miRNAs as biomarkers lies in their high tissue specificity, and their exceptional stability in the most routine preservation methods for biopsies, including Formalin Fixed Paraffin Embedded (FFPE) block. It has been suggested that their small size (19-21 nucleotides) enables them to remain intact in FFPE blocks, as opposed to messenger RNA (mRNA), which tends to degrade rapidly in samples preserved by this method.

"This is an exciting study for us, as it validates miRview squamous' sensitivity, specificity, reproducibility and overall reliability in helping physicians accurately make this critical lung cancer classification," said Ken Berlin, president and CEO of Rosetta Genomics. "The outstanding performance of our miRview squamous test underscores our ability to harness the power of microRNAs through our proprietary technology platforms. We are using this ability to further unleash the promise of microRNA and to advance our pipeline of products and the standard of medical care."

Related Links:
Johns Hopkins University
Rosetta Genomics Laboratories