Background/Aims: Assessment of malignant potential in gastrointestinal stromal tumor (GIST) is still problematic. The maximum tumor diameter and the mitotic index are generally used as an index of malignancy of GISTs. The Ki-67 labeling index has recently been used as an index of cell growth. The aim of this study was to investigate the prognostic value of Ki-67 in GIST. Methods: We retrospectively reviewed the medical records of 32 patients with GIST who underwent surgical resection at Inje University Seoul Paik Hospital. We analyzed their Ki-67 expression, histologic finding, and prognosis. Results: According to the tumor size and mitotic count, 4 patients were classified as very low risk, 9 patients as low risk, 14 patients as intermediate risk and 5 patients as high risk. The average Ki-67 index was 5.56±4.48%. The median follow-up duration was 35.72±29.04 months, and local/distant recurrences were observed in 6 (18.7%) patients. The overall cumulative disease free survival rates in patients with Ki-67 index ≤5% at 1 year, 2 years, and 5 years were 100%, 100%, and 86%, respectively. The overall cumulative disease free survival rates in patients with Ki-67 index ＞5% were at 1 year, 2 years, and 5 years were 82.1%, 70.3%, and 46.9%, respectively. There was significant relationship between elevated Ki-67 and disease free survival rate (p=0.007). Conclusions: Our study suggests that Ki-67 index ＞5% confers a higher risk of relapse in patients with GIST. Future work should focus on standardization of Ki-67 assessment and specification of its role in making treatment decisions. (Korean J Gastroenterol 2014;64:87-92)

Infliximab might play an important role for the treatment of steroid-refractory UC. Well-designed prospective trials based on the efficacy and safety of infliximab are required in the future.

Spontaneous bacterial peritonitis (SBP) is the most common infection in liver cirrhosis patients, and is not a result of surgery or intra abdominal infection. Argon plasma coagulation (APC) is an endoscopic procedure used with a high-frequency electrical current for control of bleeding from gastrointestinal vascular ectasias including angiodysplasia and gastric antral vascular ectasia. This procedure is known to be safe because it uses a noncontact method. Therefore, tissue injury is minimal and up to two to three millimeters. However, we experienced a case of SBP occurring immediately after performance of APC for control of severe bleeding from angiodysplasia in the colon in a patient with liver cirrhosis and hepatocellular carcinoma.