Non-Hodgkin lymphoma and GIST: molecular pathways and clinical expressions

Coincident primary breast lymphoma and gastrointestinal stromal tumor: case series and molecular mechanisms

Gastrointestinal stromal tumor (GIST) is an uncommon mesenchymal tumor, and has been shown to be associated with synchronous or metachronous second malignancies. Rare cases of coincident GIST and non-Hodgkin lymphomas (NHL) have been reported previously. Here, we report two cases of GIST and coincident primary breast lymphoma, an uncommon subtype of extranodal NHL. We propose that the exceedingly low likelihood of both these cancers occurring in these two patients by chance warrants examination for possible common oncogenic pathways in these lesions, possibly involving shared anti-apoptotic mechanisms. Further research is vital to elucidate common oncogenic pathways between such rare lesions.

Additional malignancies in patients with gastrointestinal stromal tumors (GIST): incidence, pathology and prognosis according to a time of occurrence-based classification

BACKGROUND

The aim of the study is to clarify if a classification based on the time of occurrence of associated malignancies in GIST patients can help in the understanding of the clinical controversies observed in these patients.

METHODS

We retrospectively reviewed all the patients diagnosed with GIST tumors between January 1999 and October 2016. They were divided into GIST patients associated with other tumors (A-GIST) and those not associated (NA-GIST). A-GIST patients were also divided into four types according to the proposed classification.

RESULTS

Of 104 GIST patients, 32 (30.7%) (A-GIST group) had at least one additional primary malignancy. The most frequent location of the associated malignancy was the GI tract (26%). Compared to NA-GIST, A-GIST were more often asymptomatic with a lower risk of recurrence. The main cause of death in NAGIST was GIST itself, being associated tumors the main cause of death in A-GIST group. No differences were found in DFS and OS between A-GIST and NA-GIST.

CONCLUSIONS

The use of the proposed classification classifies GIST patients with associated malignancies in different subtypes that differ substantially in terms of incidence, type of neoplasms associated, cause of the association and prognosis.

Upregulated ZO-1 correlates with favorable survival of gastrointestinal stromal tumor

Zonula occludens-1 (ZO-1) is a membrane-scaffolding protein that plays an important role in maintaining tight-junction integrity, which is disrupted in many invasive cancers and intestinal diseases. However, the expression of ZO-1 in gastrointestinal stromal tumor (GIST) and its relationship with clinical characteristics of this disease remain poorly understood. In this study, immunohistochemical analysis using tissue microarray was employed to evaluate the expression of ZO-1 in GIST and to investigate the relationship between its expression and GIST prognosis. High ZO-1 expression was displayed in 71.8 % of GIST patients, which was related to tumor diameter (p < 0.05). The Kaplan-Meier method and log-rank test indicated that high ZO-1 expression, small tumor diameter, tumor position in the esophagus, and a borderline-to-intermediate tumor grade displayed significant correlations with longer survival of GIST patients. The data suggest that ZO-1 expression is correlated with malignant phenotypes of GIST and it may serve as a favorable prognostic factor for GIST. These results also support a role for ZO-1 as a tumor-suppressor gene in GIST.

Gastrointestinal stromal tumor mesenchymal neoplasms: the offspring that choose the wrong path

Gastrointestinal stromal tumors (GISTs) are relatively rare neoplasms of the gastrointestinal tract originating from the pluripotential mesenchymal stem cells, which differentiate into interstitial Cajal cells. They are usually located in the upper gastrointestinal track. These tumors are typically defined by the expression of c-KIT (CD117) and CD34 proteins in the tumor cells. A small percentage of these tumors is negative for c-KIT. The neoplasms are positive for platelet-derived growth factor α (PDGFα) mutations. In addition to PDGFRα mutations, wild-type c-KIT mutations can also be present. The therapeutic approach to locally developed gastrointestinal stromal tumors is surgical resection, either with open or laparoscopic surgery. In case of systemic disease, molecular pharmacologic agents such as imatinib and sunitinib are used for treatment. These agents block the signaling pathways of neoplastic-cell tyrosine kinases, interfering in their proliferation and causing apoptosis.