Comparison of tyrosine kinase receptors HER2, EGFR, and VEGFR expression in micropapillary urothelial carcinoma with invasive urothelial carcinoma.

Invasive micropapillary urothelial carcinomas (MPUC) emerge at higher stages and follow a more aggressive course than conventional invasive urothelial carcinomas (UC). Little is known about the target therapies using tyrosine kinase inhibitors in MPUC. This study is to investigate potential effectiveness of tyrosine kinase receptor inhibitors by determining expression of epidermal growth factor receptor (EGFR), human epidermal receptor 2 (HER2), and vascular endothelial growth factor receptor 2 (VEGFR) proteins in MPUC and UC. 16 cases of MPUC and 16 stage-matched UC were identified. Immunohistochemistry for EGFR, HER2, and VEGFR2 and HER2 gene amplification by fluorescence in situ hybridization (FISH) were performed. HER2 and EGFR proteins were expressed in MPUC and UC, with significantly higher HER2 expression in MPUC (ratio 1.82, p < 0.01). HER2 gene amplification was identified in 4 of 16 MPUC (25 %). Amplification was limited to cases with 3+ HER2 expression (100% concordance). EGFR expression in MPUC was slightly higher than UC but not statistically significant (ratio 1.57, p = 0.19). EGFR and HER2 coexpression was noted in 75% of MPUC and 37.5% of UC. No VEGFR expression was identified in the urothelium. Strong VEGFR expression was noted in stromal vessels in both MPUC and UC. In conclusion, EGFR and HER2 are potential targets for neoadjuvant chemotherapy in MPUC and UC. There is no direct anti-tumor effect expected for VEGFR inhibitors.

Analysis of T-cell clonality using laser capture microdissection and high-resolution microcapillary electrophoresis.

Identification of clonal lymphocytic populations by polymerase chain reaction may be difficult in cases with scant cellular infiltrates or those with a heterogeneous population of cells. Here, we assessed the diagnostic utility of laser capture microdissection (LCM) and high-resolution microcapillary electrophoresis in the analysis of clonality of small biopsy specimens. Clonality was determined in 24 cases: five reactive tonsils, five reactive lymph nodes, six inflammatory skin lesions, and eight T-cell lymphomas. CD3-positive T lymphocytes were captured by LCM from paraffinized immunohistochemically stained sections. Genomic DNA was analyzed for T-cell receptor-gamma gene rearrangement by polymerase chain reaction followed by high-resolution microcapillary electrophoresis with the DNA 500 LabChip and the Agilent Bioanalyzer. In the reactive specimens, T-cell receptor-gamma polymerase chain reaction revealed monoclonal bands when 10 to 1000 cells were captured. This pattern changed to polyclonal when higher numbers of cells were microdissected (2000 to 10,000 cells). In contrast, lymphoma cells were consistently monoclonal whether low or high numbers were microdissected. Microcapillary electrophoresis coupled with LCM facilitated clonality analysis in equivocal cases. In two of eight lymphoma cases, LCM revealed diagnostic monoclonal bands, whereas routine T-cell receptor-gamma assessment of whole tissue sections with 10% polyacrylamide gel electrophoresis demonstrated only minor clonal bands. We conclude that clonality determined by LCM is cell number-dependent. Biopsy specimens containing low numbers of reactive polyclonal T cells may produce pseudomonoclonal bands and therefore should be interpreted with great caution.