Immunodetection of Cytoplasmatic Membrane-Bound Thrombomodulin in Formalin-Fixed Paraffin-Embedded Human Tissue Microarrays

Abstract

Background: Loss of thrombomodulin immunoreactivity denotes a poor prognosis for patients presenting with malignant disease. Objectives: Immunodetection for cytoplasmatic membrane-bound thrombomodulin in formalin-fixed paraffinembedded (FFPE) tissue microarrays. Methods: Thrombomodulin immunoreactivity was assessed in 97 FFPE tissue cores representing bladder, kidney, prostate, testis, penis, ovary, cervix, vulva, endometriosis, and myometrium, from 84 patients arrayed on three TMAs (64 (66%) cancers, 22 (23%) normal controls, and 11 (11%) benign pathologies). Human bladder tissue lysate from matched normal urothelium and TCC biopsies were also examined by western blot analysis for thrombomodulin expression. Results: Thrombomodulin immunoreactivity was strongest in the TCC cores where ≥60% of the tissue sections scored +3, or greater. By contrast, SCCs, adenocarcinomas, CCCs, papillary carcinoma, sarcomas, seminomas, teratoma and all other tissue sections scored ≤ +2. Thrombomodulin expression was also detected by western blot analysis in the human bladder tumour lysate. No signal was detected in adjacent normal control. Conclusion: Cytoplasmatic membrane-bound thrombomodulin immunostaining is strongest in TCC sections with respect to SCC, adenocarcinoma, sarcoma, seminoma, teratoma, papillary carcinoma, CCC, and is independent of both grade and stage. Thrombomodulin immunostaining in tumour tissue sections are predominately membranous.