Luca Messerini

Lymph node recovery from colorectal tumor specimens: recommendation for a minimum number of lymph nodes to be examined.

Lymph node involvement is the mostimportant prognostic factor for patients who have undergone radicalsurgery for colorectal carcinoma. An accurate examination of thesurgical specimens is mandatory for the correct assessment of the lymphnode status of the tumor. The risk of understaging is particularly highfor patients with tumors classified as Dukes B (TNM stage II). The aimof this study was to determine if a specified minimum number of lymphnodes examined per surgical specimen could have any effect on theprognosis of patients who had undergone radical surgery for Dukes Bcolorectal cancer. Between 1988 and 1995 a total of 140 patientsunderwent radical resection of Dukes B colorectal cancer by the samesurgeon (C.C.). The relation between clinicopathologic variables andsurvival was estimated using the Kaplan-Meier method. The Coxproportional hazard regression model was used to identify the variablesthat can independently influence survival. A median of 12 lymph nodes(range 3–38) was examined per tumor specimen. The 5-year survival rateof Dukes B patients who had had eight or fewer lymph nodes examinedafter surgery was 54.9%, whereas the survival rate for those who hadhad nine or more lymph nodes examined was 79.9% (p < 0.001). Cox regression analysis identified the number of lymph nodes asthe only independent prognostic factor (p = 0.01).Seventy patients with one to four metastatic lymph nodes (Dukes Cpatients) who had been operated on during the same period were includedin the survival analysis for comparison. The 5-year survival rate ofthe Dukes B patients with eight or fewer lymph nodes examined wassimilar to that of the 70 Dukes C patients (54.9% and 51.8%,respectively). Examination of eight or fewer lymph nodes in Dukes Bcolorectal patients may be considered a high risk factor for missingpositive lymph nodes in the surgical specimens. Our results suggestthat harvesting and examining a minimum of nine lymph nodes persurgical specimen may be sufficient for reliable staging of lymphnode-negative tumors.

herg1 Gene and HERG1 Protein Are Overexpressed in Colorectal Cancers and Regulate Cell Invasion of Tumor Cells

The acquisition of the capacity to invade surrounding tissues confers a more malignant phenotype to tumor cells and is necessary for the establishment of metastases. The understanding of the molecular mechanisms underlying cell invasion in human solid tumors such as colorectal cancers could provide not only more sensitive prognostic analyses but also novel molecular targets for cancer therapy. We report in this article that K+ ion channels belonging to the HERG family are important determinants for the acquisition of an invasive phenotype in colorectal cancers. The herg1 gene and HERG1 protein are expressed in many colon cancer cell lines, and the activity of HERG channels modulates colon cancer cell invasiveness. Moreover, the amount of HERG1 protein expressed on the plasma membrane is directly related to the invasive phenotype of colon cancer cells. Finally, both the herg1 gene and HERG1 protein were expressed in a high percentage of primary human colorectal cancers, with the highest incidence occurring in metastatic cancers, whereas no expression could be detected either in normal colonic mucosa or in adenomas.

Cyclooxygenase-2 Activation Mediates the Proangiogenic Effect of Nitric Oxide in Colorectal Cancer

Purpose: Up-regulation of both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) enzymes has been reported in colorectal cancer. We aimed at evaluating the possible interaction between the nitric oxide and COX-2 pathways, and its effect on promoting tumor angiogenesis. Experimental Design: Expression of iNOS, COX-2, vascular endothelial growth factor (VEGF), and CD31 was analyzed in tumor samples and corresponding normal mucosa obtained from 46 surgical specimens. We also evaluated iNOS activity, prostaglandin E2 (PGE2), cyclic GMP and cyclic AMP production in the same specimens. Nitrite/nitrate levels, and PGE2 and VEGF production were assessed in HCT116 and HT29 colon cancer cell lines after induction and selective inhibition of the two enzyme pathways. Results: A significant correlation was found between iNOS and COX-2 immunohistochemical expression. PGE2 production significantly correlated with iNOS activity and cGMP levels. A significant correlation was also found among PGE2 production, microvessel density, and VEGF expression. Coinduction of both iNOS and COX-2 activities occurred after lipopolysaccharide (LPS) and epidermal growth factor (EGF) treatment in HCT116 and HT29 cells. Inhibition of iNOS by 1400W significantly reduced both LPS- and EGF-induced PGE2 production. Treatment with LPS, EGF, and arachidonic acid significantly increased VEGF production in the iNOS-negative/COX-2-positive HT29 cells. This effect was completely reversed by treatment with the selective COX-2 inhibitor celecoxib. Conclusions: Our data showed a prominent role of nitric oxide in stimulating COX-2 activity in colorectal cancer. This interaction is likely to produce a cooperative effect in promoting angiogenesis through PGE2-mediated increase in VEGF production.

Inducible Nitric Oxide Synthase Expression in Human Colorectal Cancer : Correlation with Tumor Angiogenesis

To investigate the potential involvement of the nitric oxide (NO) pathway in colorectal carcinogenesis, we correlated the expression and the activity of inducible nitric oxide synthase (iNOS) with the degree of tumor angiogenesis in human colorectal cancer. Tumor samples and adjacent normal mucosa were obtained from 46 surgical specimens. Immunohistochemical expression of iNOS, vascular endothelial growth factor (VEGF), and CD31 was analyzed on paraffin-embedded tissue sections. iNOS activity and cyclic GMP levels were assessed by specific biochemical assays. iNOS protein expression was determined by Western blot analysis. iNOS and VEGF mRNA levels were evaluated using Northern blot analysis. Both iNOS and VEGF expressions correlated significantly with intratumor microvessel density (r(s) = 0.31, P = 0.02 and r(s) = 0.67, P < 0.0001, respectively). A significant correlation was also found between iNOS and VEGF expression (P = 0.001). iNOS activity and cyclic GMP production were significantly higher in the cancer specimens than in the normal mucosa (P < 0.0001 and P < 0.0001, respectively), as well as in metastatic tumors than in nonmetastatic ones (P = 0.002 and P = 0.04, respectively). Western and Northern blot analyses confirmed the up-regulation of the iNOS protein and gene in the tumor specimens as compared with normal mucosa. NO seems to play a role in colorectal cancer growth by promoting tumor angiogenesis.

Inhibition of 5-lipoxygenase by MK886 augments the antitumor activity of celecoxib in human colon cancer cells

Cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LOX) are key enzymes involved in arachidonic acid metabolism. Their products, prostaglandins and leukotrienes, are involved in colorectal tumor development. We aimed at evaluating whether combined blocking of the COX-2 and 5-LOX pathways might have additive antitumor effects in colorectal cancer. The expression/activity of COX-2 and 5-LOX were assessed in 24 human colorectal cancer specimens. The effects of the COX-2 inhibitor celecoxib and the 5-LOX inhibitor MK886 on prostaglandin E2 and cysteinyl leukotriene production, tumor cell proliferation, cell apoptosis, and Bcl-2/Bax expression were evaluated in the Caco-2 and HT29 colon cancer cells. We also investigated the effect of the enzymatic inhibition on mitochondrial membrane depolarization, one of the most important mechanisms involved in ceramide-induced apoptosis. Up-regulation of the COX-2 and 5-LOX pathways was found in the tumor tissue in comparison with normal colon mucosa. Inhibition of either COX-2 or 5-LOX alone resulted in activation of the other pathway in colon cancer cells. Combined treatment with 10 μmol/L celecoxib and MK886 could prevent this activation and had additive effects on inhibiting tumor cell proliferation, inducing cell apoptosis, decreasing Bcl-2 expression, increasing Bax expression, and determining mitochondrial depolarization in comparison with treatment with either inhibitor alone. The administration of the ceramide synthase inhibitor fumonisin B1 could prevent some of these antineoplastic effects. In conclusion, our study showed that inhibition of 5-LOX by MK886 could augment the antitumor activity of celecoxib in human colorectal cancer. [Mol Cancer Ther 2006;5(11):2716–26]

Primary signet-ring cell carcinoma of the colon and rectum

PURPOSE: Colorectal signet-ring cell carcinoma (SRCC) is uncommon; discordant data have been previously reported about clinicopathologic features. Thirty-four cases of primary colorectal SRCC were retrospectively reviewed to clarify controversies. METHODS: Primary colorectal SRCC was diagnosed when the following criteria were satisfied: 1) the tumor was primary; 2) histologic material was adequate; 3) signet-ring cell represented more than 50 percent of the cancer. RESULTS: We identified 34 cases (1.1 percent) of 2,995 consecutive large bowel cancers collected at the Institute of Anatomic Pathology of Florence between 1985 and 1993. Patients ranged in age from 31 to 89 (mean, 63.5; median, 65) years; 19 were male, and 15 were female (male:female=1.3∶1). Fifteen tumors were located in the proximal colon, 11 in the rectum, and 8 in the distal colon. The gross shape was infiltrative in 24 cases and exophytic in 10; only 6 cases (17.6 percent) showed features of linitis plastica. Most cancers (61.8 percent) were Stage C, 29.4 percent were Stage B, and distant metastases were present in only three cases (8.8 percent). No Stage A case was found. Prognosis was extremely poor, and overall five-year survival rate was 9.1 percent. Survival was influenced significantly by tumor stage (P<0.01). CONCLUSIONS: Comparison of our data with the literature showed many differences that could be related to different applied diagnostic criteria. We underlined the importance of histology as reproducible criterion for diagnosis of primary colorectal SRCC.

Adjuvant Chemotherapy in Completely Resected Gastric Cancer: A Randomized Phase III Trial Conducted by GOIRC

BACKGROUND Complete surgical resection of gastric cancer is potentially curative, but long-term survival is poor. METHODS Patients with histologically proven adenocarcinoma of the stomach of stages IB, II, IIIA and B, or IV (T4N2M0) and treated with potentially curative surgery were randomly assigned to follow-up alone or to intravenous treatment with four cycles (repeated every 21 days) of PELF (cisplatin [40 mg/m(2), on days 1 and 5], epirubicin [30 mg/m(2), days 1 and 5], L-leucovorin [100 mg/m(2), days 1-4], and 5-fluorouracil [300 mg/m(2), days 1-4] in a hospital setting. Frequencies and severity of adverse events were determined. Overall survival (OS) and disease-free survival (DFS) were compared between the treatment arms using Kaplan-Meier analysis and a Cox proportional hazards regression model. All statistical tests were two-sided. RESULTS From January 1995 through September 2000, 258 patients were randomly assigned to chemotherapy (n = 130) or surgery alone (n = 128). Patient characteristics were well balanced between the two arms. Among those who received chemotherapy, grade 3 or 4 toxic effects including vomiting, mucositis, and diarrhea were experienced by 21.1%, 8.4%, and 11.8% of patients, respectively. Leucopenia, anemia, and thrombocytopenia of grade 3 or 4 were experienced by 20.3%, 3.3%, and 4.2% of patients, respectively. After a median follow-up of 72.8 months, 128 patients (49.6%) experienced recurrence and 139 (53.9%) deaths were observed, one toxicity-related. Relative to treatment with surgery alone, adjuvant chemotherapy did not increase disease-free survival (hazard ratio [HR] of recurrence = 0.92; 95% confidence interval [CI] = 0.66 to 1.27) or overall survival (HR of death = 0.90; 95% CI = 0.64 to 1.26). CONCLUSIONS Our results failed to provide proof of an effect of adjuvant chemotherapy with PELF on overall survival or disease-free survival. The estimated effect of chemotherapy (10% reduction in the hazard of death or relapse) is modest and consistent with the results of meta-analyses of adjuvant chemotherapy without platinum agents.

h-caldesmon, Calretinin, Estrogen Receptor, and Ber-ep4: A Useful Combination of Immunohistochemical Markers for Differentiating Epithelioid Peritoneal Mesothelioma From Serous Papillary Carcinoma of the Ovary

Distinguishing between epithelioid peritoneal mesothelioma and papillary serous carcinomas involving the peritoneum may be very difficult, owing to overlapping morphologic features. Immunohistochemistry may facilitate establishing a correct diagnosis, but, as no single antibody has demonstrated absolute sensitivity and specificity for either mesothelioma or serous carcinoma, the differential diagnosis is based mainly on the combined use of several markers. The purpose of this study was to ascertain the sensitivity and specificity of a series of mesothelial markers [including more recently investigated antigens such as h-caldesmon (h-CD) and D2-40] and, using receiver operating characteristic curve analysis, to identify a selected appropriate panel of antibodies for differentiating between epithelioid peritoneal mesothelioma and serous papillary carcinoma of the ovary. Fifteen cases of epithelioid peritoneal mesothelioma and 40 cases of papillary serous carcinoma of the ovary (25 primary and 15 metastatic to the peritoneum) were immunostained for h-CD, D2-40, calretinin, cytokeratin 5/6, thrombomodulin, estrogen and progesterone receptors (ER and PR), Ber-EP4, B72.3, CA19-9, and CD15. h-CD and calretinin showed the highest sensitivity (100%), followed by D2-40 (93.3%) and cytokeratin 5/6 (93.3%); thrombomodulin had the lowest sensitivity (60%). h-CD and thrombomodulin had the best specificity (95%) for mesothelioma, followed by calretinin (87.5%), D2-40 (80%), and cytokeratin 5/6 (72.5%). Among carcinoma markers, ER and Ber-EP4 demonstrated the highest sensitivity (95%) followed by B72.3 (72.5%), PR (65%), CA19.9 (60%), and CD15 (45%). The specificity of the nonmesothelial markers was 100%, except for Ber-EP4 (93.3%). The relationship between the values of sensitivity and specificity of each marker using receiver operating characteristic analysis permitted the identification of h-CD, calretinin, ER, and Ber-EP4 as the markers with the best performance in differentiating epithelioid peritoneal mesothelioma from serous papillary carcinoma of the ovary.

APC gene mutations and colorectal adenomatosis in familial adenomatous polyposis

Correlations between germline APC mutation sites and colorectal pathophenotypes, as evaluated by the direct count of adenomas at colectomy, were investigated analysing colectomy specimens from 29 FAP patients carrying one mis-sense (codon 208) and 14 frame-shift or non-sense APC mutations (codons 232, 367, 437, 623, 876, 995, 1061, 1068, 1075, 1112, 1114, 1309, 1324, 1556). The mis-sense mutation at codon 208 was associated with a relatively mild colorectal pathophenotype. The mutation at codon 367, subject to alternative splicing, was associated with attenuated FAP. The mutation at codon 1309 was associated with the profuse colorectal adenomatosis. For 13 mutations, predicted to result in null alleles or truncated APC proteins, we correlated density and distribution of colorectal adenomas with the predicted functional effects of the mutation. The most severe colorectal pathophenotype was significantly associated with the truncating mutation at codon 1309, which is located downstream to the I β-catenin binding domain but upstream II β-catenin-binding domain. Mutations between codons 867 and 1114, which affect the I β-catenin binding domain, as well as mutations occurring in exons 6 and 9, predicted to result in null alleles, were associated with a less severe colorectal pathophenotype. Overall, the highest number of adenomas was detected in the right colon, followed by the left colon, transverse colon sigma and rectum. However, the highest density of adenomas was observed in the left colon, followed by the right colon, sigma, transverse colon and rectum. Colorectal carcinomas, observed in only five patients, were all in the left colon.

The Role of Cyclooxygenase-2 in Mediating the Effects of Histamine on Cell Proliferation and Vascular Endothelial Growth Factor Production in Colorectal Cancer

Purpose: Activity of histidine decarboxylase, the key enzyme in the synthesis of histamine, has been shown to be increased in several types of human tumors. We attempted to establish whether the possible involvement of histidine decarboxylase and histamine in colorectal carcinogenesis might be mediated by the activation of the cyclooxygenase-2 (COX-2) pathway. Experimental Design: Expression/activity of histidine decarboxylase, histamine content, and prostaglandin E2 (PGE2) production were analyzed in 33 colorectal cancer samples and in the HT29, Caco-2, and HCT116 colon cancer cell lines. The effects of histamine, celecoxib, and H1, H2, and H4 receptor antagonists on COX-2 expression/activity, cell proliferation, and vascular endothelial growth factor (VEGF) production were assessed in the three colon cancer lines that showed different constitutive COX-2 expression. Results: We showed the up-regulation of histidine decarboxylase protein expression and activity in the tumor specimens when compared with normal colonic mucosa. Histidine decarboxylase activity and histamine content were also significantly higher in metastatic tumors than in nonmetastatic ones. These variables significantly correlated with tumor PGE2 production. The administration of histamine increased COX-2 expression/activity, cell proliferation, and VEGF production in the COX-2-positive HT29 and Caco-2 cells. Treatment with either H2/H4 receptor antagonists or celecoxib prevented these effects. Histamine had no effect on both the COX-2 pathway and VEGF production in the COX-2-negative HCT116 cells. Conclusions: Our data showed that histamine exerts both a proproliferative and a proangiogenic effect via H2/H4 receptor activation. These effects are likely to be mediated by increasing COX-2-related PGE2 production in COX-2-expressing colon cancer cells.