Gastrointestinal stromal tumors and KIT‐positive mesenchymal cells in the omentum

Abstract

Gastrointestinal stromal tumor (GIST) is currently considered to be derived from the interstitial cells of Cajal (ICC). To test the hypothesis that omental mesenchymal tumor is also a type of GIST, we evaluated the expression of specific molecules in GIST, and c-kit gene mutation in omental mesenchymal tumors, and we identified a possible counterpart of ICC in the omentum. Immunohistochemically, all of the omental mesenchymal tumors (n = 5) were positive for both KIT and CD34, and three of the five tumors were also positive for an embryonic form of smooth-muscle myosin heavy chain (SMemb). Polymerase chain reaction-single-strand conformational polymorphism analysis (PCR-SSCP) and direct sequencing revealed mutations in c-kit gene exon 11 in all five tumors. As for the ICC counterparts in the omentum, there were some KIT-positive mesenchymal cells resembling ICC at the surface of the omentum. Double fluorescence immunostaining, using anti-KIT polyclonal antibodies and monoclonal antibodies against other molecules, demonstrated that KIT-, CD34- and SMemb-positive cells were present just beneath the mesothelial cells of the omentum. These results show that omental mesenchymal tumor corresponds to GIST of the omentum, and that KIT-positive bipolar mesenchymal cells may be a counterpart of ICC in the gastrointestinal tract. Identification of a new type of KIT-positive mesenchymal cell in the omentum may lead to the discovery of a new physiological role for this organ.

Mutations in c‐kit Gene Exons 9 and 13 in Gastrointestinal Stromal Tumors among Japanese

“…In our previous studies regarding mutation in c-kit gene exon 11 by PCR-SSCP analysis, lack of a normal allele was seen in some GISTs in the tubular GI tract and the omentum. 11,16) Two cases of GISTs with exon 13 mutation reported by Lux et al also lacked wild-type KIT sequences. 13) Loss of 4q11-12, where the c-kit gene is located, has not been reported using comparative genomic hybridization, 17) microsatellite markers 18) and fluorescence in situ hybridization.…”

The Role of the Surgeon in Multidisciplinary Approach to Gastrointestinal Stromal Tumors

“…They found all five tumors to be positive for CD117 and CD34 staining, while all were negative for smooth-muscle cell markers. More importantly, the authors reported finding KIT immunoreactive CD117 and CD34 cells within specimens of omentum (Sakurai S et al;2001). These findings and those of Yamamoto et al underscore the fact that histologically, EGISTs have a similar appearance to GISTs, and that EGIST is a distinctive entity, different from leiomyosarcomas 1999).…”

“…It is not well known if extra-gastrointestinal stromal tumors (EGIST) originate from pacemaker cells outside of the GI tract or if mesenchymal cells have the ability to recapitulate the phenotype. Sakurai et al (Sakurai S et al;2001), published their results on the cytological, immunohistochemical, and genetic analysis of 5 omental mesenchymal tumors in 2001. They found all five tumors to be positive for CD117 and CD34 staining, while all were negative for smooth-muscle cell markers.…”

“…These findings and those of Yamamoto et al underscore the fact that histologically, EGISTs have a similar appearance to GISTs, and that EGIST is a distinctive entity, different from leiomyosarcomas 1999). The most common mutation of the KIT gene occurred in exon 11 in Sakurai's and Yamamoto's experience (Sakurai S et al;2001, Yamamoto H et al;. GIST arising from Meckel's diverticulum are extremely rare (Johnston AT et al;2001).…”

Omental Leiomyoma in a Male Adult Horse

“…8,9,16,18 However, the cellular origin of these so-called extragastrointestinal stromal tumors (EGISTs) is not known, and the occurrence of EGISTs is still discussed controversially. 1 One study could find KIT-positive mesenchymal cells in the normal human omentum; 24 in another study, most cases of EGISTs were re-diagnosed as metastases of normal GISTs or as GISTs that have arisen from the outer muscle coat of the gastrointestinal tract and lost their contact due to an extensive extramural growth pattern.…”