Immunohistochemical expression of chemokine receptor in neuroendocrine neoplasms (CXCR4) of the gastrointestinal tract: a retrospective study of 71 cases.

AIM: C-X-C motif chemokine receptor 4 (CXCR4) is expressed in many tumor entities, including gastrointestinal neuroendocrine neoplasms (GI-NENs). However, the role of CXCR4 expression in GI-NENs has been less studied. Our objective was to investigate the expression of CXCR4 in a series of GI-NENs with various clinical and pathological features. METHODS: The immunohistochemical (IHC) expression of CXCR4 (clone UMB2) was examined in 71 GI-NENs and a semiquantitative immunoreactivity score (IRS) was calculated taking into consideration the intensity of the IHC reaction and the percentage of the tumor cells which showed positive expression. Results were compared with several clinical and pathological prognostic factors. RESULTS: High CXCR4 expression was noted in 31 (43.7%) cases. Low IRS values were more frequent in NENs from the small intestine (66.7%) and stomach (60%). Also, all appendix tumors had IRS value of zero. High CXCR4 expression was noticed in 52.5% of liver metastases, compared to 40.4% primary tumors. A significant relationship was observed between the CXCR4 expression and the tumor grade (p=0.0216), and high IRS value was correlated with clinical stages III and IV (p=0.0142) and lympho-vascular invasion (p=0.0129). 74.1% of G1 neuroendocrine tumors (NETs) had a low IRS, G3 NETs showed minor differences between low (42.9%) and high (57.1%) expression and 66.7% of neuroendocrine carcinomas (NECs) presented high expression of CXCR4. CONCLUSIONS: The present study highlighted that high CXCR4 expression is associated with high grade and advanced stage GI-NENs, as well as with metastatic cases. In these cases, high CXCR4 expression could serve as an important target for CXCR4 antagonists.

The new WHO classification of gastrointestinal neuroendocrine tumors and immunohistochemical expression of somatostatin receptor 2 and 5.

The 2019 World Health Organization (WHO) classification of gastrointestinal tumors defines well-differentiated grade 3 neuroendocrine tumors, the mixed neuroendocrine-non-neuroendocrine tumors (MiNENs) and classifies goblet cell carcinoid as goblet cell adenocarcinoma. The expression of somatostatin receptors (SSTRs) is the foundation for somatostatin analogue therapy. At present, there are only a few studies that have analyzed the immunohistochemical reactivity of SSTRs in gastrointestinal neuroendocrine neoplasms (NENs). The aim of the present study was to evaluate the immunohistochemical expression of SSTR2 and SSTR5 in gastrointestinal NENs and goblet cell adenocarcinomas and the correlation of these markers with clinical and morphological factors. The study included 67 patients with NENs and 4 patients with adenocarcinoma ex-goblet cell carcinoid diagnosed between January 2008 and December 2018. Tumors were reclassified according to the 2019 WHO classification. Immunohistochemical staining for chromogranin A, synaptophysin, Ki-67, p53, SSTR2, and SSTR5 were performed in all the cases. The results showed that, G1 and G2 neuroendocrine tumors were more common SSTR2-positive in comparison with G3 carcinomas (P<0.0001). In addition, 33.3% of neuroendocrine carcinomas and 2 cases of low-grade adenocarcinoma ex-goblet cell carcinoid were SSTR2-positive. Neuroendocrine carcinomas had significantly lower SSTR2 and SSTR5 expression compared with well-differentiated neuroendocrine tumors (P=0.0130; P=0.0437, respectively). The SSTR2 expression in the early tumor stages was 100%, more often than in advanced stages (55.6%; P=0.0011). The results demonstrated the decrease in SSTR2 expression with increasing malignancy and tumor stage. The SSTR2-positive expression in neuroendocrine carcinomas and adenocarcinoma ex-goblet cell carcinoid provides evidence for the benefits of somatostatin analog treatment associated with surgery and chemotherapy.

Unexpected diagnosis for a gastric polyp: Granular cell tumor: Case report and review of the literature.

A granular cell tumor (GCT) is a rare neoplasia that originates from Schwann cells. It usually appears in the skin or soft tissues, but it may occur anywhere in the body. The gastrointestinal tract is an unusual developmental site for a GCT, the esophagus being the most common site of origin for this tumor. The stomach is one of the most unique sites of origin for GCT, with less than 80 cases being mentioned in the literature. Histologically, GCTs consist of fusiform and polygonal cells, with granular cytoplasm, arranged in compact 'nests'. Immunohistochemically, these tumors show positivity for S100 protein, CD68, CD56 and, in a smaller percentage, they are positive for other antibodies, most notably inhibin alpha. We report the case of a 52-year-old woman with a solitary GCT that had developed in the gastric cardia, discovered on a routine gastroscopy and successfully treated by endoscopic submucosal dissection.