[399] Immunohistochemical Expression Profile of Metastatic Urothelial Carcinoma Using Cell Block Cytology: Comparison of Novel Markers S100P and GATA3 to Traditional Urothelial Markers

MN de Peralta-Venturina, R Parakh, SV Smith, SR Kini. Cedars Sinai Medical Center, Los Angeles, CA; Henry Ford Hospital, Detroit, MI

Background: Immunohistochemical stains currently used as markers for urothelial differentiation are of limited sensitivity and specificity. S100P and GATA3 are novel markers of urothelial carcinoma identified using DNA microarrays and tissue microarrays (Am J Surg Pathol 2007; 31: 673-680). To date, no study using cytologic material has compared these two potential antibodies with traditional urothelial markers namely CK903, p63, uroplakin and thrombomodulin.
Design: 23 patients with clinically metastatic urothelial carcinoma who had positive cytologic specimens with adequate cell block were identified from the files of two institutions. Clinical information was gathered from the electronic medical record. Immunohistochemistry was performed on cell block material using monoclonal antibodies for p63 (Biocare Medical), CK903 (Cell Marque), uroplakin (Fitzgerald), thrombomodulin (Dako), S100P (BD Biosciences) and GATA3 (Santa Cruz Biotechnology. Double immunostaining technique was used for CK903 and p63. The staining intensity was evaluated on a scale of 0 to 3+, and the extent as 1+ to 3+ (<25%, 25-50%, >50%).
Results: There were 18 males and 5 females with mean age of 73 years. Specimens consisted of 15 fine needle aspiration biopsies (lymph nodes 6, liver 3, lung 3, bone 3) and 8 body fluid samples (pleural fluid 5, peritoneal 3). All 23 cases (100%) showed immunoreactivity for thrombomodulin with at least moderate to strong staining in 22 cases (96.5%). CK903 and p63 showed at least moderate intensity of staining in 19 (83%) and 18 (78%) of cases. Uroplakin stained only 1 case (4%). S100P and GATA3 showed cytoplasmic staining in 19 (83%) and nuclear staining in 14 (61%) of cases, respectively. However, staining was more commonly focal with both new antibodies compared with the 3 conventional markers; which tended to show more intense and diffuse staining.
Conclusions: In this study, thrombomodulin is the most useful marker in confirming the urothelial nature of metastatic carcinoma using cell block cytology. CK903 and S100p have similar sensitivity which is superior to either p63 or GATA3. A panel consisting of thrombomodulin and CK 903 with or without p63 or S100p is useful in the work-up of patients suspected of having metastatic urothelial carcinoma using cell block cytology.
Category: Cytopathology

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 102, Tuesday Morning

 

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