Gastric cancer is one of the most common malignancies in China. Currently, surgical resection, chemotherapy and radiotherapy are still the main therapeutic methods.The postoperative 5-year survival of patients with gastric cancer is lower than 60%. As a means of adjuvant therapy, immunotherapy has the potential to improve the survival of patients with gastric cancer, because its therapeutic targeting and toxicity profile does not overlap with those of conventional therapies. The effector cells of the immune system (T, B and NK cells), when activated, are able to lyse and destroy tumor cells through specific recognition of tumor-associated antigens. However, most immunotherapy research in gastric cancer is still limited to the preclinical stage due to the weakness of its antigenicity. With the development of tumor immunobiology and genetic engineering, immunotherapy has become the focus of research for the treatment of gastric cancer.

Synchronous colorectal liver metastases occurs in 15%-25% of patients with newly diagnosed colorectal cancer. Hepatic resoction has been accepted as the only option that offers long-term survival for patients with liver metastases. However, the optimal timing and sequence of resection for synchronous colorectal liver metastases still remain controversial. Also, the use of neoadjuvant chemotherapy which should be initiated in patients with resectable synchronous liver metastases is not consistent. In order to use evidence-based medicine to clarify indications for one-stage hepatic resection of liver metastases, a multi-center clinical trial was pedormed to normalize the surgical strategy of synchronous liver metastases. In summary, in selected patients, one-stage approach is comparable to the two-stage procedure in mortality and morbidity rates and longterm survival. One-stage procedure should be performed according to the site of primary tumor, age, the volume of residual healthy liver. Preoperative chemotherapy is effective in downstaging the tumor and reducing the resected liver volume, but it also brings damage to the liver and has adverse effect on onestage hepatic resection.

Objective To investigate the clinicopathological features of multiple primary colorectal carcinoma. Methods The clinical data of 30 patients with multiple primary colorectal carcinoma and 580 patients with single colorectal carcinoma who were admitted to the Peking University People's Hospital from January 2001 to March 2008 were retrospectively analyzed. There were 16 patients with multiple synchronous carcinoma and 14with multiple metachronous carcinoma. The survival of the patients was analyzed using Kaplan-Meier method and the survival rates were compared using Log-rank test. All data were analyzed using the chi-square test. Results The onset age of multiple metachronous primary carcinoma was younger than that of multiple synchronous carcinoma and single colorectal carcinoma, while the onset age of multiple metachronous secondary carcinoma was close to that of multiple synchronous carcinoma and single colorectal carcinoma. Most of the synchronous carcinoma located at the left colon; while most of the metachronous primary carcinoma located at the rectum and sigmoid colon, and most of the metachronous secondary carcinoma located at the ascending colon. Patients with multiple synchronous carcinoma or multiple metachronous primary carcinoma received radical resection. Of the 14 patients with multiple metachronous carcinoma, 9 received radical resection for secondary focus. Except for three patients with multiple synchronous carcinoma and two patients with multiple metachronous carcinoma, all patients received postoperative chemotherapy with FCF, FOLFOX or XELOX regimen. Of the 580 patients with single colorectal carcinoma, 512 received radical resection, 68 received palliative operation, and 519 received postoperative chemotherapy. The cumulative survival rate of patients with multiple metachronous primary carcinoma was significantly higher than that of single colorectal carcinoma (x2 = 17. 289, P ＜ 0. 05). There was no significant difference in the cumulative survival rate between patients with single colorectal carcinoma and those with multiple metachronous secondary carcinoma or multiple synchronous carcinoma (x2 = 1.731, 0. 800, P ＞ 0. 05). Conclusion The prognosis of patients with colorectal multiple metachronous carcinoma is better than those with single colorectal carcinoma, and the prognosis of colorectal synchronous carcinoma is similar to those with single colorectal carcinoma.

The Notch signaling pathway represents control cell proliferation, differentiation and apoptosis during development.Aberrant activation of this pathway contributes to tumorigenesis and genes in the Notch signaling pathway could be potential therapeutic targets.This review involves regulation of Notch pathway and molecular targeted therapy.

The actual incidence of gastrointestinal stromal tumor (GIST) is underestimated.With the progression of awareness and development of examination methods,the detection rate of small GIST (diameter ＜ 5 cm) is increasing year by year.These patients always had no obvious clinical symptoms,and were often detected with small GIST in physical examination unexpectedly.Combination of endoscopic ultrasound and radiographic examination is helpful in detecting small GIST.Aggressive surgical complete resection should be considered in case of a definitive diagnosis.Laparoscopic resection is becoming the standard surgical treatment currently.For micro GIST (diameter ＜2 cm),especially micro gastric stromal tumor,current guidelines recommend close observation.Some scholars advocate that endoscopic resection is feasible for the treatment of micro GIST,while we think that the efficacy of individualized treatment is better after identifying the potential malignancy of micro GIST.

Because of the characteristics of microRNAs (miRNAs) and their important regulative roles in human tumor diseases,they may be novel approaches for gene target therapy.Most studies focus on finding critical regulator miRNAs of oncogenes or tumor suppressor genes.Recent researches show that the expression of miR-221 and miR-222 are abnormal,and they play different roles in different types of human tumors.The regulation of miR-221 and miR-222 may be a novel effective therapy for tumor.

Metastatic cancer is often occurred in advanced digestive system tumors and the most involved organ is liver.Multiple therapeutic managements and strategies such as surgery,systemic chemotherapy,radiofrequency ablation,portal vein embolization and transarterial chemoembolization are used in the treatment of liver metastasis.However,the treatment of advanced digestive system tumors liver metastasis is still challenging,different therapeutic methods show different results for different tumors,comprehensive treatment should be used based on features of patients and muliidisciplinary cooperation.With the accumulation of clinical experiences,the emergence of novel chemotherapeutics,wider indications of surgical resection in treating liver metastases and accumulated evidence from randomized controlled trials,the therapeutic management of metastatic hepatic cancer should be standardized and more effective in the future.

Objective To investigate the expression of p53 up-regulated modulator of apoptosis (PUMA) and p53 protein and relationship with clinicopatbological parameters in human gastric cancers. Methods Primary gastric carcinoma and adjacent normal mucosa were obtained from 84 consecutively enrolled patients undergoing gastric cancer resection at Peking University People's Hospital during the period from April 2001 to May 2003. Immunohistochemistry staining was used to measure the expression of PUMA and p53 proteins both in normal and malignant tissues. Results PUMA expression is significantly weaker in primary gastric carcinoma compared to adjacent normal mucosa (P <0. 01 ). Weak PUMA expression in gastric cancer correlates with depth of tumor invasion ( P < 0. 01 ), advanced pTNM stage ( P < 0. 05 ) and poor overall survival of patients ( P < 0. 05 ). p53 protein expression in gastric carcinoma is significantly higher than adjacent normal mucosa ( P < 0. 01 ). There was a significant negative correlation between the expression of PUMA protein and p53 protein in gastric carcinoma (P < 0. 05 ). Conclusion PUMA expression in gastric carcinoma is significantly lower compared to adjacent normal mucosa. Weak PUMA expression in gastric cancer correlates with depth of tumor invasion, later pTNM stage and poor overall patient survival.

Objective To evaluate KISS1 expression, and its significance in the prognosis of GIST patients. Methods In this study, 137 GIST cases and 73 non-GIST sarcoma cases were evaluated for clinicopathological characteristics and immunohistochemistry for KISS1 antibodies. Result The expression rate of KISS1 was 40.9% (56/137) in GISTs,which was significantly correlated with tumor size, disease extent, cellularity, presence of pseudocapaule, Fletcher's risk stratification and metastatic status after resection (P＜0.05). Patients with positive KISS1 expression had significantly worse disease free survival and disease specific survival (P ＜ 0.05 ). Conclusions KISS1 expression was associated with some clinicopathological characteristics as well as malignant behaviors in patients with GISTs. KISS1 might be a predictor in prognosis for GIST patients.