Prospective study of FGFR3 mutations as a prognostic factor in nonmuscle invasive urothelial bladder carcinomas.
OBJECTIVE
To determine the frequency and the prognostic value of fibroblast growth factor receptor 3 (FGFR3) mutations in patients with nonmuscle invasive bladder tumors according to tumor stage and grade.


METHODS
Seven hundred seventy-two patients with newly diagnosed bladder tumors were recruited. Tumors were reviewed by expert pathologists. Patients were prospectively followed-up (median, 62.6 months for disease-free patients) through review of hospital records and telephone interviews. The sequence of exons 7 and 10 of FGFR3 was analyzed by polymerase chain reaction and direct sequencing. We assessed the association of mutations with stage and grade. The predictive value of mutations for recurrence, progression, and mortality were assessed using Kaplan-Meier and Cox multivariable models.


RESULTS
Mutations were more common among low malignant potential neoplasms (LMPN; 77%) and TaG1/TaG2 tumors (61%/58%) than among TaG3 tumors (34%) and T1G3 tumors (17%). The S249C, Y375C, S248C, and G372C mutations accounted for 91.5% of all sequence changes. The A393E substitution was associated with LMPN (P < .001). The F386L polymorphism was more frequent among patients with low-grade tumors (odds ratio, 6.97; 95%CI, 1.40 to 47.06; P = .009). In the multivariable analysis of all superficial tumors, mutations were associated with increased risk of recurrence. However, in the stratified analyses only patients with TaG1 tumors had a significantly higher risk of recurrence (hazard ratio, 2.12; 95%CI, 1.28 to 3.53; P = .004).


CONCLUSIONS
The findings of this large study strongly support the notion that FGFR3 mutations characterize a subgroup of bladder cancers with good prognosis; patients with mutant TaG1 tumors have a higher risk of recurrence; and the F386L variant is selectively associated with low-grade tumors.
Hernández
Silvia
S
Universitat Pompeu Fabra, Institut Municipal d'Investigació Mèdica, Hospital del Mar, Barcelona, Spain.
López-Knowles
Elena
E
Lloreta
Josep
J
Kogevinas
Manolis
M
Amorós
Alex
A
Tardón
Adonina
A
Carrato
Alfredo
A
Serra
Consol
C
Malats
Núria
N
Real
Francisco X
FX
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000409:Alanine; D003545:Cysteine; D005260:Female; D018698:Glutamic Acid; D005998:Glycine; D006801:Humans; D007930:Leucine; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D010649:Phenylalanine; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012694:Serine; D014443:Tyrosine; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000473:pathology
D018698:Glutamic Acid; D014443:Tyrosine; D012694:Serine; D010649:Phenylalanine; C496365:FGFR3 protein, human; D051498:Receptor, Fibroblast Growth Factor, Type 3; D007930:Leucine; D003545:Cysteine; D000409:Alanine; D005998:Glycine