Deficiency of Adenomatous Polyposis Coli protein in sporadic colorectal adenomas and its associations with clinical phenotype and histology.
OBJECTIVE
To evaluate the frequency of the loss of the Adenomatous Polyposis Coli (APC) protein and to compare the APC status with the characteristics of colorectal adenomas.


METHODS
Immunohistochemical analysis of the APC protein was performed on 118 adenomas and the results were compared with parameters of malignant potential, location of adenomas, macroscopic appearance and age of the patients.


RESULTS
A complete loss of the APC protein was found in 28 (24%) adenomas, while 90 (76%) were APC positive. The mean size of adenomas was 13.5 +/- 14.2 mm (95% CI 10.5-16.5) in APC-positive, and 13.8 +/- 15.5 mm (95% CI 7.8-19.8) in APC-negative adenomas (P = 0.364). Statistical analysis revealed no difference between APC-positive and negative adenomas as to the histological type (P = 0.327) and grade of dysplasia (P = 0.494). We found that even advanced adenomas did not differ in their APC status from the non-advanced tumors (P = 0.414). Finally, no difference was found when the location (P = 0.157), macroscopic appearance (P = 0.571) and age of patients (P = 0.438) were analysed and compared between both APC positive and negative adenomas.


CONCLUSIONS
Most adenomas expressed full-length APC protein, suggesting that protein expression is not a reliable marker for assessment of APC gene mutation. Complete loss of APC protein did not influence morphology, location, or appearance of adenomas, nor was it affected by the patient's age.
Bortlik
Martin
M
Gastroenterology Center, 4th Internal Department, General Faculty Hospital, 1st School of Medicine, Charles University, Prague, Czech Republic. mbortlik@hotmail.com
Vitkova
Ivana
I
Papezova
Martina
M
Kohoutova
Milada
M
Novotny
Ales
A
Adamec
Stanislav
S
Chalupna
Petra
P
Lukas
Milan
M
D000236:Adenoma / Q000737:chemistry / Q000235:genetics* / Q000473:pathology*; D025601:Adenomatous Polyposis Coli Protein / Q000032:analysis / Q000235:genetics*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D015179:Colorectal Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology*; D004252:DNA Mutational Analysis; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D012720:Severity of Illness Index
D025601:Adenomatous Polyposis Coli Protein; D014408:Biomarkers, Tumor