Urinary insulin-like growth factor 2 identifies the presence of urothelial carcinoma of the bladder.
OBJECTIVE
To examine urinary insulin-like growth factor 2 (IGF-2) levels in patient urine samples and determine the potential of IGF-2 as a marker for the presence of urothelial carcinoma of the bladder (UCB).


METHODS
The current gold standard for diagnosis of UCB is cystoscopy and cytological analysis. The identification of an accurate urine marker for UCB with the potential to replace unnecessary cystoscopy would benefit patients with UCB and others investigated after detecting haematuria. In the present study, we analysed 65 urine samples, and optimized an enzyme-linked immunosorbent assay-based approach to measure urinary levels of IGF-2.


RESULTS
Based on a threshold of 5.4 ng/mL, patients with UCB have significantly elevated levels of urinary IGF-2 (P = 0.009) and this difference remained significant after adjustment for age and sex (P = 0.04). Sensitivity and specificity values of 80% and 52%, respectively, were determined for urinary IGF-2 alone and when combined with nuclear matrix protein 22 (NMP22; an approved biomarker for detection of UCB). There was a positive correlation between urinary IGF-2 levels and NMP22 levels in patient urine samples and the combined assay improved the detection of UCB (sensitivity 85% and specificity 52%).


CONCLUSIONS
Substantiated evidence has identified IGF-2 as a valuable marker for UCB. In addition, the novel observations of the present study have shown that aberrant levels of IGF-2 occurring in the presence of UCB, can now be determined through a simple and inexpensive urine assay.
Watson
Jenny A
JA
The UCD School of Medicine and Medical Sciences, University College Dublin, Ireland. jennywatson2008@gmail.com
Burling
Keith
K
Fitzpatrick
Patricia
P
Kay
Elaine
E
Kelly
John
J
Fitzpatrick
John M
JM
Dervan
Peter A
PA
McCann
Amanda
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000652:urine*; D002295:Carcinoma, Transitional Cell / Q000175:diagnosis* / Q000652:urine; D015331:Cohort Studies; D003558:Cystoscopy; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000652:urine; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000652:urine; D055815:Young Adult
D014408:Biomarkers, Tumor; D009687:Nuclear Proteins; C100379:nuclear matrix protein 22; D007335:Insulin-Like Growth Factor II