Utility of the laminin immunohistochemical stain in distinguishing invasive from noninvasive urothelial carcinoma

Dinesh Pradhan, Milon Amin, Shveta Hooda, Rajiv Dhir, Sheldon Bastacky, Anil V Parwani

Journal of Cancer Research and Therapeutics 2017 13(6):947-950

Background: To study the utility of the laminin immunostain in distinguishing invasive from noninvasive urothelial carcinoma (UC). The distinction is difficult but clinically significant as it can affect the decision to administer intravesical Bacillus Calmette–Guerin or can even lead to cystectomy. Materials and Methods: Representative sections of the transurethral resection of bladder tumor specimens from 25 cases of formalin-fixed paraffin-embedded invasive UCs and 25 cases of noninvasive UCs were selected for immunohistochemical (IHC) staining with laminin (Ventana, Oro Valley, AZ, USA). These cases were selected using a computer-assisted search of our laboratory information system (Cerner CoPath). Tissue from five paraffin-embedded tissue blocks containing unremarkable urothelial-lined bladder parenchyma was chosen as controls. Results: All five control cases demonstrated crisp linear staining of the basement membrane underlying the unremarkable urothelium. Similar findings were also noted in the 25 cases of noninvasive UC. All 25 cases of the invasive UC demonstrated a complete absence of the staining around invasive and malignant urothelial cells. Laminin staining was also noted in both the muscularis mucosae and the detrusor muscle, although the pattern of staining in these areas was granular and was distinguishable from the crisp linear staining of the basement membrane. Conclusion: Laminin IHC staining can be useful in differentiating invasive from noninvasive UC.

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