It has been reported that NIH3T3 cells treated with sublethal levels of DEM to induce ROS defense genes such as xCT and glutathione-S-transferase ��1 (GST��1) are associated with higher resistance to various apoptotic stimuli such as buthionine sulphoximine, ultraviolet, and things etoposide (Faraonio et al, 2006). Moreover, HT22 hippocampal cells resistant to oxidative stress exhibited a 7-fold overexpression of xCT mRNA, with a concomitant increase in resistance to glutamate-induced oxidative stress and hydrogen peroxide-induced ox
Gastrointestinal stromal tumor (GIST) is the most common soft tissue tumor of the gastrointestinal tract. It was reported that GIST derived from interstitial cells of Cajal is characterized by the expression of CD34 and c-kit (CD117).

Immunohistochemical positivity for c-kit gene product-CD117, a tyrosine kinase receptor, reflects the presence of gained function of c-kit gene mutation[1]. Imatinib mesylate (IM) (Glivec; Novartis Pharmaceuticals, Basel, Switzerland) is a small-molecule tyrosine kinase inhibitor that suppresses the mutated c-kit product[2]. Clinical trials[3,4] for recurrent or metastatic GIST have demonstrated that the partial response (PR) rate is 47% to 54% based on radiographic evaluation. However, a complete response (CR) is rarely reported. Pathologically verified cases showing therapeutic efficacy have been rarely reported. Up to present, only seven cases of locally advanced or metastatic GIST with a pathologic CR to IM treatment have been reported in the literature[5�C10].

The initial treatment for a metastatic GIST is to use IM, and then surgical treatment directing toward complete resection is to be considered when the tumor has responded and reduced in size[11�C13]. However, neither the adequate intervals between the start of treatment with IM and operation, nor the significance of surgical resection for the patients with metastatic GIST who have been treated with IM, has been completely elucidated. In this paper, we present a case of GIST with meta-chronous liver metastasis treated with IM, and describe confirmed the therapeutic efficacy of such a molecular targeting drug as IM, which was confirmed by virtue of pathologic CR following complete surgical resection. CASE REPORT A 39-year-old male complaining of epigastralgia was found to have a 3 cm �� 2 cm submucosal tumor on the anterior surface of the body along the lesser curvature of the stomach, and underwent partial gastrectomy.

Pathological examination of the surgical specimen revealed a high grade Cilengitide leiomyosarcoma showing spindle cells with 20 mitoses/10HPF and 17% in the MIB-1 index. The patient was subsequently diagnosed as having an uncommitted type of high grade GIST, since he was immunohistochemically positive for CD34 and CD117 (Figure (Figure1).1).