[Development of therapeutic antibodies for gastric and colorectal cancers].

With the elucidation of structures and functions, antibodies are widely applied in the diagnosis and treatment of diseases. Today, therapeutic antibodies have played ever increasing roles in the treatment of cancers. In fact, there are over 20 monoclonal antibodies which have been approved by the U.S.Food and Drug Administration (FDA) for the therapeutic use in cancers. For the gastric and colorectal cancers, there are at least 9 antibodies have been approved for cancer therapy or for clinical trials. These antibody drugs target to tumor associate antigens and can destroy the cancer cells through several mechanisms such as antibody-dependent cell cytotoxicity, complement-dependent cytotoxicity, blockage of blood nutrition and crucial signaling pathways. With the progress in gene engineering technology, the diverse structures of antibodies can be created. In addition, the antibody-conjugates with radioisotopes, toxins and cytotoxins, are also designed for targeted therapy of gastric and colorectal cancers. In this article, we review the trends in the clinical development and application of antibody drugs for future research and development of the rapidly expanding therapeutic modality in gastric and colorectal cancers.

A study on the CD(4) (+) CD (25) (+) regulatory T cells in patients with gastrointestinal malignancies.

OBJECTIVES: Regulatory T cells play an active role in the maintenance of the immune system's tolerance of both foreign and self antigens. Particularly, CD(4) (+) CD(25) (+) regulatory T cells participate in tumor immunity. The study provided further evidence on the involvement of CD(4) (+ )CD(25) (+) regulatory T cells in immune system impairment in patients with gastrointestinal malignancies. METHODS: Using flow cytometry, CD(4) (+ )CD(25) (+) regulatory T cells were analyzed in peripheral blood from 114 patients with gastrointestinal malignancies and 15 healthy controls. RESULTS: The prevalence of the CD(25) (+) subset in CD(4) (+) T cells was increased in patients with colorectal carcinoma compared with healthy controls. The phenotic characteristics of the CD(4) (+ )CD(25) (+) T cells in patient with malignancies were low expression of CD(45) RA and no expression of CD(69). Our results indicated that when compared with healthy control, the proportions of CD(4) (+) CD(25) (+) T cells in the peripheral blood of patients with colorectal, gastric, and esophageal carcinoma were significantly higher (P < 0.05) in colorectal carcinoma (22.11 +/- 9.65%), gastric carcinoma (17.74 +/- 4.24%), and esophageal carcinoma (24.37 +/- 4.82)%, respectively. Further analysis on the proportion of CD(4) (+ )CD(25) (+) T cells revealed that those patients with gastrointestinal malignancies in stages IV were higher than those of in stage I-III, though no significant difference was observed (P > 0.05). However, the proportion of CD(4) (+ )CD(25) (+) T cells in the patients with relapse gastric carcinoma (23.32 +/- 4.98%) was significantly higher than that of patients with primary gastric carcinoma (P < 0.01). CONCLUSIONS: The increased CD(4) (+ )CD(25) (+) T cells in patients with gastrointestinal malignancies may be related to immunosuppression and tumor progression. This suggests that elimination or reduction of CD(4) (+ )CD(25) (+) regulatory T cells can improve effective tumor immunity for immunotherapy.