S106 Abstracts uate by immunoistochemistIy (BrdU detection kit II, Roche, Milan). Cellular migratiou was evaluated by counting the BrdU marked cells and calculating the difference between the marked cells at 24 and 72 hours, expressed as percentage (ll. %). Statistical analysis of the data was performed by Wilcoxon test. was analyzed by RT-PCR and Western Blotting (anti Santa Cruz, California). Results: As shown in table, at 72 hours, 9%, 21% and 40% of colonic marked cells disappeared in A, Band C groups respectively. At the same time points, mRNA was decreased while protein levels were increased in dose dependent manner. sub-set of patients with less advanced MSI sporadic disease. In contrast, Pl6 methylation is associated with advanced disease, a feature largely explained by increasing prevalences of advanced stages in females with this epigenetic alteration. PA.146 THE IN VIVO EFFECT OF AUGMENTER OF LIVER REGENERATION (ALR) ON SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION·3 (STAT3) FACTOR Table 1. BrdU+ cells/lOO cells counted in 8 well oriented cripts Tunes Group A Group B Group C 24 hrs 12.2±1.3 13.6±1.0 14.4±1.0 48 hes 12.4±1.9 13.9±2.1 14.5± 0.6 72 hes 11.1±1.l 1O.7±2.7 8.7±1.4 -9 -21 -40 L. Polimeno .,1, B. Pesetti 1, E. Annoscia 1, G. Ingravallo 2, M. Valente 1, A. Amoruso 1, A. Francavilla 1 ISez ione di Gastroenterologia edEndoscopia Digestiva, DErO, Universitii degli Studi, Bari 2Universitii di Bari, Bari Conclusions: Silymarin administration determines an increase of levels, probably by a post-transcriptional mechanism, and a concomi- tant increase of the cellular migration. Since these data suggest an anti tumor effect of silymarin, we will test its biological activity in an experimental model of intestinal tumorigenesis PA.145 INFLUENCE OF GENDER AND OF P16 METHYLATION ON TUMOR STAGE OF COLORECTAL CANCERS WITH MICROSATELLITE INSTABILITY L. Laghi', P. Bianchi, A.E. Randolph, M. Roncalli, A. Malesci Istituto Clinico Humanitns, Rozzano (MI) Background and aim: hMLHI and Pl6 promoter methylation occur frequently in colon cancers with microsatellite instability (MSI); while hMLH1 methylation is associated with sporadic MSI, the features of MSI tumors associated with Pl6 methylation are less clear. To eval- uate the correlation of hMLHI and Pl6 epigenetic alterations, as to demographics, inheritance, and pathological features of a series of MSI colo-rectal cancers (CRC). Material and methods: We studied hMLHI and Pl6 methylation in 88 (MIF, 50/38) MSI CRC, comprising 25 (MIF, 15/10) hereditary non- polyposis CRC (Amsterdam Criteria), and 63 (MIF, 34/29) sporadic cases. Tumor were staged by AJCC criteria. Results: Out of 88 MSI CRC, 59 (67%) had methylation of hMLHI (MIF, 28/31; p=O.OI), and 45 (51 %) of Pl6 (MIF, 29/16; hMLHl vs Pl6 methylation in females, p=0.0004). Methylation of hMLHI only occurred in 21 (24%) CRC (MIF, 6/15; p=0.003) and of Pl6 only in 7 (8%; MIF, 7/0; p=O.OI). In 63 sporadic MSI CRC, 49 (77%) showed methylation of hMLHI (MIF 24/25), and 37 (59%) of Pl6 (MIF, 23/14), hMLHI being more frequently methylated than Pl6 in females (p=0.002). Upon univariate analysis, CRC stage 3-4 (29, 33%) were more frequent in males than in females (MIF 21/8; p=0.03), in CRC with methylated than in those with unmethylated Pl6 (21/45, vs 8/43; p=O.OO5), and in proximal than distal tumors (27/69, vs 2/19; p=0.02). In sporadic cases, only Pl6 status was significantly associated with advanced stages (4/26 in un-methylated vs 19/37 in methylated CRC; p=0.003). Upon multivariate analysis, proximal location and Pl6 methylation were independently associated with advanced tumor stage (p=0.04 and p=O.OI, respectively) in all cases, but only Pl6 in sporadic disease (p=0.003). Accordingly, in females, we observed 7 stage 3-4 cancers out of 16 with methylation of both Pl6 and hMLHl, as com- pared with 1 (7%) out of 15 with only hMLHI methylation (p=0.03). Conclusions: Prevalences of hMLHI methylated MSI CRC are high in old patients with sporadic disease, while Pl6 is more frequently methylated in stage 3-4 than in stage 1-2 cancers. The combination of female gender and hMLHl-only methylated cancers can identify a Background and aim: STATs are a family of transcription factors activated by a wide variety of extracellular polypeptides including EGF, PDGF and IL-6. Recent studies have shown a Stat3 activation (Ser- and Tyr-phosphorylation) in the murine partial hepatectomy model (PH) that induces anti-apoptotic factors such as bcl-2, bcl-xL, attributing to Stat3 an anti-apoptotic role in liver regenerative process. Recently, Augmenter of Liver Regeneration (ALR), a hepatic growth factor, has been identified as a control factor of the apoptotic process that occurs after PH. The present work has been done to evaluate if ALR exerts its apoptotic effect through Stat3 activation. Material and methods: Stat3 expression and its activation were evalu- ated on livers from rAlrp-treated or not animals. Two sets of experiments have been performed. In the first, Stat3 was evaluated, by Western Blot, on hepatic cytosol from 35 intact mice, divided in 7 groups of 5 each. Three groups received, i.p., a single injection ofrAlrp (500 ng) and three groups a same dose of albumin (control). Five treated- and 5 control- mice were sacrificed at 3, 12 and 24 hrs each time. Five animals (time zero) were sacrificed after injection. In the second, Stat3 expression and its phosphorylation were evaluated by immunohistochemistIy tech- niques on liver sections from 70% PH rats. 35 male rats underwent PH and were divided in 7 groups of 5 animals each. Three groups (treated) were injected, i.p., with multiple doses of rAlrp (500 ng/rat/every 12 hrs) starting from the 18th hour after PH and sacrificed at 24, 36,48 hrs after surgery; three groups (control) received a similar dose of albumin following the same protocol. Five animals (time zero) were sacrificed after PH. Results: The first group of experiments show a statistically significant (p<O.OI) increase of Stat3 at 12 and 24 hrs. In the second group of experiments an increase of Stat3 protein was registered in partially hepatectomized rAlrp-treated rats at 24 and 36 hrs after surgery, com- pared to control animals. Most importantly, a statistically significant increase of Stat3-Ser-P was observed at 24 hrs after PH in partially hepatectomized rAlrp-treated rats, compared to control animals. Conclusions: The results show that ALR is able to induce Stat3 and its phosphorylation. These data contribute to clarify the molecular pathway of ALR. PA.147 THE HSI,2A ENHANCER ALLELE 2 SHOWS AN INCREASED FREQUENCY IN PATIENTS WITH CROHN'S DISEASE D. Frezza, C. Petruzziello, M. Cretella, E. Calabrese, S. Onali, V. Giambra, C. Mattioli, F. Pallone, L. Biancone Universitii "Tor Vergatn", Roma Background and aim: The genetics of Crohn's Disease (CD) is char- acterised by multiple susceptibility loci, genetic heterogeneity and incomplete penetrance. The 3' regulatory complex of the genes of the Ig heavy chain constant region encompass at least 3 enhancers: the central