[1] SIR MORTIMER B DAVIS JEWISH HOSP, DEPT CYTOL, MONTREAL, PQ H3T 1E2, CANADA
[2] MCGILL UNIV, MONTREAL, PQ, CANADA
[3] INST ARMAND FRAPPIER, DEPT EPIDEMIOL, MONTREAL, PQ, CANADA
[4] INST ARMAND FRAPPIER, DEPT BIOSTAT, MONTREAL, PQ, CANADA
[5] ROYAL VICTORIA HOSP, DEPT PATHOL, MONTREAL, PQ H3A 1A1, CANADA
[6] PRESBYTERIAN MED CTR, DEPT PATHOL, DENVER, CO 80218 USA
[7] PRESBYTERIAN MED CTR, DEPT OBSTET & GYNECOL, DENVER, CO 80218 USA
[8] COLUMBIA UNIV, COLL PHYS & SURG, DEPT PATHOL, NEW YORK, NY 10025 USA
[9] COLUMBIA UNIV, COLL PHYS & SURG, DEPT OBSTET & GYNECOL, NEW YORK, NY 10025 USA