This Week in Modern Pathology

University of California, Los Angeles, researchers report in Modern Pathology that the 2007 guidelines from the American Society of Clinical Oncology and the College of American Pathology did not lead to improvements in concordance rates between HER2 and ERBB2 testing. The researchers performed both immunohistochemical analysis for the HER2 protein and fluorescence in situ hybridization assay for the ERBB2 gene on formalin-fixed, paraffin-embedded human breast cancer tissue samples from 1,437 patients with invasive breast carcinoma. Some of the cases were scored according to FDA guidelines and the rest according to 2007 guidelines from ASCO/CAP. The researchers saw no difference in concordance rate using the different guidelines. "At our institution, implementation of the new ASCO/CAP scoring guidelines did not significantly influence HER2 testing concordance rates nor was there a decrease in immunohistochemically equivocal/inconclusive cases," the UCLA researchers write.

Also in Modern Pathology, researchers at the Royal National Orthopedic Hospital NHS Trust in Stanmore, UK, present their work on examining whether MDM2 amplification can be used as a marker to distinguish lipomas from atypical lipomatous tumors. Using a commercially available MDM2 fluoresence in situ hybridization kit, the researchers assessed 227 lipomatous and 201 non-lipomatous tumors, and they report that there is a correlation between tumors' MDM2 amplification and the microscopy-based diagnosis. The researchers write that "the findings indicate that MDM2 amplification is 93.5 [percent] sensitive for diagnosing atypical lipomatous tumor." They add that the "MDM2 FISH test is a useful adjunct to histology for distinguishing lipoma from atypical lipomatous tumor."