Clinical relevance of proliferation biomarkers and p53 expression in rectal mucosa and sporadic colonic adenomas: a prospective study.
OBJECTIVE
Prospective study to evaluate 1) the pattern of proliferation biomarkers and p53 expression in rectal mucosa and adenomatous tissue, and 2) the clinical relevance of these biomarkers as predictors for adenoma recurrence.


METHODS
40 patients with sporadic adenomas underwent colonoscopic polypectomy and rectal biopsies. Assessment of proliferation biomarkers--Ornithine decarboxylase, PCNA and Ki-67--was done in adenomas and rectal mucosa, while p53 was performed in adenomas. After polypectomy, 34 adenoma patients were followed for 36 months to detect metachronous polyps. 20 controls underwent colonoscopy and rectal biopsies, with assessment of proliferation biomarkers.


RESULTS
Mean values of ornithine decarboxylase, PCNA and Ki-67 in rectal mucosa from adenoma patients were not significantly different when compared with the control group. The expression of these biomarkers was significantly increased in adenomas versus rectal mucosa. Only 6 (15%) out of 40 adenomas were found to overexpress p53 protein. During follow-up, recurrent polyps were detected in 12 patients (relapsing group). Mean values of ornithine decarboxylase, detected at index colonoscopy, were not significantly higher in relapsing group versus non-relapsing group. Mean values of PCNA and Ki-67 detected in adenomas at index colonoscopy were significantly higher in relapsing group when compared with non-relapsing group. Adenoma recurrence was observed in all patients with p53 overexpression.


CONCLUSIONS
Ornithine decarboxylase, PCNA and Ki-67 expression in rectal mucosa did not show clinical relevance. Yet, increased expression of PCNA or Ki-67 in adenomatous tissue may be a predictor of adenoma recurrence. Positive p53 might have the same predictive value.
Freitas
Diniz
D
Department of Gastroenterology, Coimbra University Hospital, 3046 Coimbra, Portugal. gastro@huc.min-saude.pt
Goulão
Maria Helena
MH
Camacho
Ernestina
E
Figueiredo
Pedro
P
Ministro
Paula
P
Ferreira
Manuela
M
Portela
Francisco
F
Andrade
Paulo
P
Donato
António
A
Martins
Maria Irene
MI
D000236:Adenoma / Q000378:metabolism*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003110:Colonic Neoplasms / Q000378:metabolism*; D003111:Colonic Polyps / Q000378:metabolism*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009955:Ornithine Decarboxylase / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; D009955:Ornithine Decarboxylase