Gastrointestinal stromal tumors (GISTs): focus on histopathological diagnosis and biomolecular features

Abstract

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract that are believed to originate from a neoplastic transformation of the intestinal pacemaker cells (interstitial cells of Cajal) normally found in the bowel wall or their precursors. Although the microscopic features have been known for a long time, the defining characteristic of GIST is the presence of the cell-surface antigen CD117 (KIT), which is demonstrated by immunohistochemistry. KIT, which is a growth factor transmembrane receptor, is the product of the proto-oncogene c-kit (chromosome 4). Surgical removal remains the only curative treatment for patients with GISTs. Tumor size, mitotic index, anatomic location, tumor rupture and disease-free interval are the classic characteristics used to predict the clinical course of patients who undergo complete gross resection. Most GISTs express constitutively activated mutant isoforms of KIT or kinase platelet-derived growth factor receptor alpha (PDGFRA) that are potential therapeutic targets for imatinib mesylate. Imatinib mesylate is a rationally designed, molecularly specific oral anticancer agent that selectively inhibits several protein tyrosine kinases central to the pathogenesis of human cancer and which has demonstrated remarkable clinical efficacy in patients with chronic myeloid leukemia and malignant GISTs. More recently Sunitinib, a new KIT/PDGFRA kinase inhibitor, has been tested in patients with GIST resistant to imatinib, with promising results.

Down-regulation of miR-221 and miR-222 correlates with pronounced Kit expression in gastrointestinal stromal tumors

“…GISTs show a typical histomorphology with either a spindle, epithelioid, or mixed cell type. The characteristic immunohistochemical feature is the frequent expression of Kit and CD34 in most of the tumors (1)(2)(3).…”

Bladder extragastrointestinal stromal tumor in an adolescent patient: A case-based review

“…The thoroughness of surgical treatment is closely associated with cure; therefore, a complete excision of the tumor by properly expanding the surgical scope is the key to EGIST treatment (17). By administering molecular-targeted drugs, such as imatinib, as neoadjuvant and adjuvant therapy for GISTs, small-scale clinical studies have achieved some clinical efficacy (18).…”

‹İnce barsak gastrointestinal stromal tümörü (GİST): Olgu sunumu

“…GIST'lerin ço¤u histolojik olarak i¤ flekilli tümör hücrelerinden, bir k›sm› ise epiteloid tümör hücrelerinden veya her ikisinin kar›fl›m› fleklinde görülürler. ‹¤ flekilli tümör hücrelerinden oluflan leiomyom veya leiomyosarkomdan ay›r›c› tan›s› histolojik olarak benzer oldu¤un-dan güç olabilir (6). Epiteloid tipin ise az diferansiye adenokarsinom, andiferansiye karsinom ve karsinoid tümörlerden ayr›m›n› yapmak önemlidir.…”

“…‹mmunohistokimyasal çal›flmalarda GIST'lerin %70-80'inde CD34 (+)'li¤i saptan›r. (2,6) GIST flüphesi varl›¤›nda izlenecek ad›mlar; -Düzgün yüzeyli, hemisferik, ülsere olmayan ve 2 cm'den kü-çük kitle saptand›¤›nda 1-2 y›lda bir endoskopik takip; takipte büyüme, ülserasyon, düzensiz s›n›r tespit edilmesi halinde BT, endoskopik USG (EUS), EUS-‹‹AB önerilir.…”