The clinical significance of HER2 protein amplification/expression in urinary bladder lesion

Objective:
To evaluate HER2 oncoprotein expression by both immunohistochemical (IHC) staining and fluorescence in situ hybridisation (FISH) in different benign and malignant bladder lesions, and the effect of bilharzial infestation on this expression.

Patients and methods:
In a prospective controlled study, 72 patients were classified into a control group, and groups with cystitis, urothelial carcinoma, and squamous cell carcinoma (SCC). HER2 was detected using standard IHC staining and FISH in all groups. The correlation of HER2 expression with tumour type, stage and grade in relation to normal urothelium and cystitis was assessed. The effect of schistosomal infestation was evaluated.

Results:
HER2 expression was statistically significantly higher in patients with malignant lesions than in the other groups, and in high-stage and -grade tumours than in low-stage and -grade tumours. The use of FISH increased the detection of HER2-positive tumours. Schistosomal infestation did not affect HER2 expression in patients with transitional cell carcinoma.

Conclusion:
High-stage and -grade bladder malignancies expressed HER2 much more than did benign lesions. FISH is more sensitive for detecting HER2 expression. The treatment of HER2-positive tumours might benefit from novel targeted-treatment protocols.