HSP90 expression: a new predictive factor for BCG response in stage Ta-T1 grade 3 bladder tumours.
OBJECTIVE
Although Bacillus Calmette-Guérin (BCG) instillations are considered as the adjuvant treatment of choice for stage Ta-T1 grade G3 bladder tumours, there is no consensus for a predictive factor to assess BCG success. This study attempted to evaluate if heat shock proteins (HSPs) could be useful predictive markers in BCG responses.


METHODS
Thirty-three primary resected G3 superficial bladder tumours were included in the study. All patients received adjuvant BCG instillations. The mean follow-up was 56 mo (range: 24-132 mo). HSP expression was evaluated by immunochemistry.


RESULTS
In the 33 patients, 18 had no recurrence (group 1), 9 had recurrence with no muscular invasion (group 2), and 6 had an invasive recurrence (group 3). A significant correlation was found between lack of expression of HSP90 and BCG response: the mean HSP expression was 92.7%, 84.4%, and 26.7% for groups 1, 2 and 3 tumours, respectively (p<0.0001). For the 6 patients who did not positively respond to BCG, HSP expression was <40%. All the tumours with a HSP90 expression >40% positively responded to BCG, corresponding to group 1 or 2 patients. In contrast, HSP60 expression was not correlated to the BCG response.


CONCLUSIONS
HSP90 could be considered as a very promising marker to assess BCG treatment response. Low HSP90 expression (<40%) could be useful to predict BCG failure and early stage cystectomy could be proposed for these selected patients with primary high-risk grade 3 superficial bladder tumours.
Lebret
Thierry
T
Department of Urology and Pathology, Hôpital Foch, Suresnes, France. t.lebret@hopital-foch.org
Watson
R William G
RW
Molinié
Vincent
V
Poulain
Jean-Eudes
JE
O'Neill
Amanda
A
Fitzpatrick
John M
JM
Botto
Henry
H
D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D001500:BCG Vaccine / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D002295:Carcinoma, Transitional Cell / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D015653:Cystectomy; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D016896:Treatment Outcome; D001749:Urinary Bladder Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy
D000276:Adjuvants, Immunologic; D001500:BCG Vaccine; D014408:Biomarkers, Tumor; D018841:HSP90 Heat-Shock Proteins