Expression of the hyaluronan receptor RHAMM in endometrial carcinomas suggests a role in tumour progression and metastasis.

PURPOSE

Interactions of hyaluronic acid (HA) with its binding protein RHAMM (receptor for HA-mediated motility) have been proposed as being important in promoting tumour progression and dissemination. This comparative study was designed to investigate the RHAMM expression patterns in endometrial carcinoma.

METHODS

We examined a series of 89 endometrial carcinomas and 15 normal endometrial tissues by immunohistochemistry, using a RHAMM-specific polyclonal antibody. Expression of RHAMM was assessed according to the pattern and intensity within (overall cytoplasm, center/periphery of tumours) and between the tumours. The staining results were compared to the corresponding clinical data (age, menopause status, histological staining, histological grading, lymph node status).

RESULTS

RHAMM-expression was detectable in 58% of the 89 tumours [Histological stage: pT1a (8/12); pT1b (16/37); pT1c (18/26); pT2 (6/9); pT3a (4/5)] and 13% (2/15) of the normal endometrial tissues. The positivity rates for RHAMM were 100% in patients with positive lymph nodes but only 50.7% in patients with negative lymph nodes ( P<0-01). Additionally, the expression pattern showed a highly significant correlation ( P<0.01) with the histological grade of the tumours [G1 (6/42), G2 (33/34), G3 (13/13)] and occurrence of lymph node metastases.

CONCLUSIONS

Our results suggest that RHAMM expression may enhance and improve the invasion and metastasis of endometrial carcinomas.