EPIDERMAL GROWTH-FACTOR RECEPTOR IN THE VESICAL UROTHELIUM OF PARAPLEGIC AND TETRAPLEGIC PATIENTS - AN IMMUNOHISTOCHEMICAL STUDY

Spinal cord injury (SCI) patients are at high risk of developing cysti tis, and vesical neoplasia. As abnormal growth regulation of urotheliu m may be a predisposing factor for cystitis and vesical neoplasia. we studied alterations if any, in the expression and localization of epid ermal growth factor receptor (EGRF) in the vesical uro thelium by an i mmuno-histochemical technique, using monoclonal mouse anti-human epide rmal growth factor receptor antibody (DAKO-EGFR1) in cold-cup biopsies taken from the trigone of the urinary bladder in 18 adult SCI patient s who had a neuropathic bladder. Abnormal localisation of EGFR-p, i.e. cytoplasmic, was noted in 13 patients. A linear localization of EGFR- p along the cell membrane of the urothelium, considered as an essentia l requirement for effective function, was observed in only three cases . Combined cytoplasmic and cell membrane location of EGFR-p was seen i n two patients. The three patients with cell membrane location of EGFR -p showed a strong expression of EGFR-p (2(+), 2-3(+), and 4(+), respe ctively); the intensity of EGFR-p expression in cases of cytoplasmic i mmunostaining varied considerably. Histopathology revealed denuding cy stitis in one, follicular cystitis in four; active inflammatory infilt rate in three, lymphocytic infiltrate in three; squamous metaplasia in six; and intestinal metaplasia in three biopsy specimens. The three s pecimens showing cell membrane location of EGFR-p were from patients w ho did not have an indwelling urethral catheter (a paraplegic man prac tising intermittent self-catheterisation, a tetraplegic patient on pen ile condom drainage, and a tetraplegic woman with reflex voiding), and histopathology revealed very little inflammatory infiltrate, In contr ast, the biopsies from all the nine patients, who were on indwelling u rethral catheter drainage and in whom the bladder biopsy revealed vary ing degree of cystitis, showed only cytoplasmic location of EGFR-p. Si milarly, the biopsies from patients with bladder stone (n=6) showed on ly cytoplasmic localisation of EGFR-p. In conclusion, abnormalities in vesical urothelial expression in EGFR in SCI patients may play a role in the pathogenesis of cystitis, vesical urothelial metaplasia, dyspl asia and neoplasia.