Digestive and Liver Disease - Volume 48 - Supplement 2

Abstracts of the 22

National Congress of Digestive Diseases / Digestive and Liver Disease 48S2 (2016) e67–e231

e85

after polypectomy, but the interaction between these factors is

still unclear. We aimed to generate a prognostic model for post-

polypectomy ACA recurrence by defining different prognostic

groups.

Material and methods:

Out of 3360 patients who underwent colon

polypectomy at University of Foggia between 2004 and 2008, data of

843 patients with 1155 ACAs was retrospectively reviewed. Recursive

partitioning analysis of predictors for 3-year post-polypectomy

recurrence was performed.

Results:

Median ACA size was 16 mm (interquartile range 12-23)

while their median number was 1.5 (1-2). Pedunculated, sessile and

non-polypoid lesions were 40.9%, 39.6% and 19.5% of ACAs detected,

respectively. Independent predictors of 3-year recurrence were

lesion size [odds ratio (OR): 3.96, 95% confidence interval: 1.87-7.55,

p<0.001], number (OR: 3.22, 2.19-5.39; p<0.001) and grade of

dysplasia (OR: 4.25, 2.11-7.50); p<0.001), as confirmed both in

logistic regression and in random forest analysis. Recursive

partitioning analysis identified three risk groups: low-risk in

presence of single ACA ≤15 mm with low-grade dysplasia (LGD),

medium-risk in case of high-grade dysplasia (HGD) ≤15 mm, LGD

>15 mm or multiple LGDs ≤15 mm, and high-risk if HGD >15 mm

(Figure 1). Three-year recurrence rate was 4.7%, 21.5% and 59.3%,

respectively (p<0.001).

Conclusions:

ACAs ≥15 mm presenting HGD are at higher risk of

recurrence and might benefit from more intensive surveillance,

while single LGD ≤15 mm could be considered for longer follow-up

intervals.

OC.04.6

EARLY DETECTION OF METACHRONOUS COLORECTAL CANCER:

THE ROLE OF FATTY ACID SYNTHASE (FASN)

Riga C.

, Corazziari E.*

, Murari R.

, Pedullà G.

, Pronio A.

, Covotta A.

Lamazza A.

, De Toma G.

, Alò P.L.

, Rivera M.

Policinico Umberto I, Roma, Italy,

ospedale Umberto I, Frosinone,

Italy

Background and aim:

Patients undergoing curative resection

of colorectal cancer have an increasing risk (from 0.6 up 9%) to

develop a metachronous tumor, being this risk higher in the first

3 years following the diagnosis. Therefore, it would be desirable

that non invasive investigations such as those based on the

analysis of markers can detect, after a therapeutic resection of

a CRC, the patients who have an increased risk of developing

a second tumor, in order to restrict the most frequent controls

only to these cases. In this study, the following markers will be

evaluated with immunohistochemistry: ki-67, a nuclear protein

which is used as an index of cell proliferation; bcl-2 an oncoprotein,

whose overexpression plays a role in the early stages of colorectal

carcinogenesis; p-53,“the guardian of the genome”, and FASN, an

enzyme that catalyzes the synthesis of long-chain fatty acids, which

are considered as a late marker of tumor progression.

The aim is to evaluate whether the expression of biological markers

such as p53, bcl-2, Ki-67 and FASN on healthy colon mucosa is

predictive of onset, presence or absence of metachronous cancer.

Material and methods:

In a prospective study consecutive

outpatients or inpatients diagnosed with CRC stage I-III were

recruited. Patients with HNPCC or IBD were excluded. All patients

underwent periodic colonoscopies during which biopsies were

performed on healthy mucosa in pre-defined colic sections. The

biological markers were assessed with immunohistochemistry on

biopsy samples.

Results:

In three year observation time a total of 16 patients

(age: 53-83 years old, M:F 8:8) were examined. Three patients

were diagnosed with synchronous lesions, four patients with

metachronous lesions and one patient experienced recurrence of

the disease. A patient, whose FASN was already positive on a healthy

colon mucosa, developed a metachronous lesion on the same site

of the positive biopsy, while in case of patients with synchronous

lesions or recurrent disease, the FASN became positive at the

same time such lesions were detected. None of the others markers

investigated were detected during the study period.

Conclusions:

The expression of FASN on healthy colon mucosa

suggests that colon cells can transiently modify their metabolism

in order to gain a greater input of energy. Therefore, the finding of

its positivity, as reported in this study, may indicated an increased

risk to develop a metachronous lesion and the need to submit such

patients to a more intensive follow-up.

OC.04.7

IDENTIFICATION OF PROTEOMIC PROFILES ASSOCIATED WITH

TUMOR REGRESSION GRADING IN RECTAL CANCER

De Re V.*, Repetto O., De Paoli A., Fornasarig M., Maiero S.,

Buonadonna A., Belluco C., Orzes E., Zucchi E., Canzonieri V.,

Cannizzaro R.

Centro di Riferimento Oncologico, Aviano, Italy

Background and aim:

Rectal cancer response to neoadjuvant chemo-

radiotherapy (CRT) is variable. Identifying markers of response will

help select patients more likely to benefit from therapy. Objective

of the study is to identify at diagnosis proteomic profiles associated

with tumor regression grading (TRG) in rectal cancer.

Material and methods:

This study includes 40 patients with rectal

cancer treated with CRT followed by surgery. Proteins from pre-

treatment tumor biopsies and control from paired normal bioptical

specimens were screened for comparative proteomic approach by

using 2D difference gel electrophoresis (2D-DIGE). Differential spots

found with Decyder were identified by MALDI-TOF and peptide

fingerprinting with Mascot search engine. Interactions among

identified proteins were analyzed with STRING 9.1 search tool.

Pathological TRG was assessed on surgical specimens.

Results:

A total of 30 proteins were identified as discriminators

between tumor samples and controls by principal component

analysis and hierarchical clustering (p<0.01; spot map>50%). These

proteins were already described as involved in rectal metabolic cell

pathways and angiogenesis. Possible correlations between these

proteins and TRG are under evaluation.

Conclusions:

Comparative proteomics approach based on 2D-DIGE

and MALDI-TOF identification succeeded in differentiating rectal

tumor samples from paired normal rectal mucosa. Further analyses

will unravel possible correlations between distinct protein profiles