The influence of retinoic acid receptor (RAR) status of bladder tumours on the course of the disease.

Retinoids influence bladder tumour development in animals and tumour recurrence in man. Some human tumours contain intracellular receptor proteins for retinoids. The effect of the presence of such retinoic acid receptors (RAR) on tumour response to conventional therapy has been studied in 59 patients. Thirty-two of 36 RAR+ve and 11 of 23 RAR-ve tumour patients were alive after a mean follow-up period of 2.6 years. Higher stage and grade were more commonly associated with RAR-ve tumours. Independent of stage, recurrence was more common in RAR-ve tumours. These studies suggest that RAR-ve tumours are more likely to recur and more likely to become invasive. However, further studies are required to determine the clinical value of RAR receptor status as a prognostic indicator.