Radical surgery offers a low probability of cure in patients with diffuse-mixed type of gastric cancer and involvement of the serosa, due to a high risk of peritoneal recurrence. These patients might benefit from adjuvant therapies to prevent peritoneal carcinomatosis.

The prognostic value of preoperative serum levels of CEA, CA 19-9 and CA 72-4 tumor markers was investigated in 153 patients resected for gastric cancer. The positivity rates for CEA, CA 19-9 and CA 72-4 were 20.9, 34.6 and 28.1%, respectively. Multiple logistic regression analysis for positive levels of tumor markers indicates that CEA positivity is significantly related to the depth of invasion (p < 0.005) and the presence of distant metastasis (p < 0.05), CA 19-9 positivity is related to nodal involvement (p < 0.05) and the depth of invasion (p < 0.05), whereas CA 72-4 positivity is influenced by tumor size (p < 0.005) and noncurative surgery (p < 0.05). Positive levels of each tumor marker were associated with a worse prognosis if compared with negative cases using univariate analysis. Multivariate analysis of curatively resected cases identified depth in gastric wall (p < 0.0001), nodal status (p < 0.0005), and tumor location in the upper third (p < 0.05) as significant prognostic variables; CEA, CA 19-9 and CA 72-4 serum positivity did not reach statistical significance. However, when the positivity of the three markers was associated, a p value < 0.05 was observed. The analysis of survival curves stratified by tumor stage revealed that marker positivity significantly affects survival in stages I, II and IV (p < 0.05). The combined assay of CEA, CA 19-9 and CA 72-4 preoperative serum levels provides additional prognostic information in patients resected for gastric cancer; patients with preoperative positivity for one of these tumor markers should be considered at high risk of recurrence even in early stages of gastric carcinoma.

The aim of this multicenter longitudinal study was to evaluate the pattern of recurrence in patients submitted to potentially curative surgery for intestinal-type and diffuse-type gastric cancer. The study included 412 patients surgically treated at three Italian surgical departments, subdivided into 273 intestinal-type cases (group A) and 139 diffuse-type cases (group B). Recurrence of disease was found in 41% of group A cases and 65% of group B cases (p < 0.0001). The incidence of locoregional, hematogenous, and peritoneal recurrence was 20%, 19%, and 9% in group A, and 27%, 16%, and 34% in group B, respectively; the difference between the two groups was statistically significant for peritoneal recurrence (p < 0.0001). Multivariate analysis identified as prognostic variables lymph node status, depth of invasion, extent of lymphadenectomy, advanced age, and male gender in group A; depth of invasion, extent of lymphadenectomy, tumor size, and lymph node status, in group B. Whereas in group A the incidence of peritoneal recurrence was limited in all subgroups examined, in group B very high rates were observed in cases with infiltration of the serosa, involvement of second-level lymph nodes, or large tumor size. The notable difference in the risk of peritoneal recurrence between the intestinal and diffuse types should be taken into consideration in the therapeutic approach to gastric cancer.

Purpose: Although the anti-EGF receptor (EGFR) monoclonal antibody cetuximab is an effective strategy in colorectal cancer therapy, its clinical use is limited by intrinsic or acquired resistance. Alterations in the "sphingolipid rheostat"-the balance between the proapoptotic molecule ceramide and the mitogenic factor sphingosine-1-phosphate (S1P)-due to sphingosine kinase 1 (SphK1) overactivation have been involved in resistance to anticancer-targeted agents. Moreover, cross-talks between SphK1 and EGFR-dependent signaling pathways have been described.Experimental design: We investigated SphK1 contribution to cetuximab resistance in colorectal cancer, in preclinical in vitro/in vivo models, and in tumor specimens from patients.Results: SphK1 was found overexpressed and overactivated in colorectal cancer cells with intrinsic or acquired resistance to cetuximab. SphK1 contribution to resistance was supported by the demonstration that SphK1 inhibition by N,N-dimethyl-sphingosine or silencing via siRNA in resistant cells restores sensitivity to cetuximab, whereas exogenous SphK1 overexpression in sensitive cells confers resistance to these agents. Moreover, treatment of resistant cells with fingolimod (FTY720), a S1P receptor (S1PR) antagonist, resulted in resensitization to cetuximab both in vitro and in vivo, with inhibition of tumor growth, interference with signal transduction, induction of cancer cells apoptosis, and prolongation of mice survival. Finally, a correlation between SphK1 expression and cetuximab response was found in colorectal cancer patients.