Molecular cytology genotyping of primary and metastatic GI stromal tumors by using a custom two-gene targeted next-generation sequencing panel with therapeutic intent

Genomic Study of Chinese Quadruple-negative GISTs Using Next-generation Sequencing Technology

PURPOSE

Approximately 10% of gastrointestinal stromal tumors (GISTs) are devoid of KIT, PDGFRA (platelet-derived growth factor-alpha), BRAF, and SDH alterations. The aim of this study was to characterize molecular drivers in Chinese patients with quadruple-negative GISTs.

PATIENTS AND METHODS

In 1022 Chinese patients with GIST, mutations of KIT and PDGFRA were analyzed by direct sequencing. Of these mutations, 142 KIT/PDGFRA wild-type (WT) GISTs were detected, and succinate dehydrogenase (SDH) deficiency was determined using immunohistochemistry analysis of succinate dehydrogenase B. In 78 KIT/PDGFRA/SDH cases, we performed targeted 425 cancer-related gene analysis using next-generation sequencing. The correlation between molecular findings and clinicopathologic features was also analyzed.

RESULTS

We defined 72 quadruple-negative GISTs from enrollments. They featured nongastric localization with histologic characteristics of spindle cells and male predilection. An overall 27.78% (20/72) of quadruple-negative tumors carried TP53, and 25.00% (18/72) carried RB1 mutations, which were frequently associated with high mitotic index and large size. TP53 analyses demonstrated coexistence with mutational activation of other oncogenes in 12 of 20 cases. A total of 18 RB1-mutated cases were independent of TP53. Further, no tumors carried NF1 and BRAF mutations.

CONCLUSIONS

We report the genomic analysis of Chinese quadruple-negative patients. These databases may help advance our understanding of quadruple-negative GISTs' progression. Next-generation sequencing from GISTs is feasible to provide relevant data for guiding individualized therapy.

Endosonography-Guided Fine-Needle Aspiration versus "Key-Hole Biopsy" in the diagnostics of upper gastrointestinal subepithelial tumors. A prospective randomized interventional study

BACKGROUND

The management and prognosis of subepithelial tumors (SETs) of the upper gastrointestinal tract depend on the correct preoperative evaluation, including tissue diagnosis in selected cases. Several methods providing deep tissue sampling for cytological and/or histological examinations have been described but their diagnostic yield and precise position in the diagnostic algorithm remain to be established. This prospective randomized study aims to compare the Endosonography-Guided Fine-Needle Aspiration (EUS-FNA) to Key-Hole Biopsy (KHB) in cytological or histological diagnostics of upper gastrointestinal SETs.

PATIENTS AND METHODS

This study was conducted in a single tertiary endoscopy center in Ostrava, Czech Republic between November 2010 and October 2015. Patients with endoscopically detected SETs of the upper gastrointestinal tract with a diameter ≥ 2 cm, were randomized to either the EUS-FNA with 22G needle, or to the Key Hole biopsy (forceps biopsy through mucosal incision) groups. The main study outcomes were success rate of tissue diagnostics and, in the cases of Gastrointestinal Stromal Tumours (GIST), possibility of determining mitotic activity. A cross-over examination was performed in situations where the first method had failed.

RESULTS

A total of 46 consecutive patients were randomized. Of these, 24 (52%) and 22 (48%) were randomized to EUS-FNA group and KHB arm, respectively. 5 SETs (11%) were detected in the esophagus, 40 (87%) in the stomach and 1 (2%) in the duodenum. The definitive diagnosis was established by the first sampling method in 42 (91%) patients, including 22 (92%) in the EUS-FNA group and 20 (91%) in the KHB group (P=0.999), and after a cross-over in another 3 (7%) patients. The most prevalent SET was GIST (70%). Although some mitotic activity could be observed in 11 patients, the mitotic index could be diagnosed in none of them. Of a total of 20 surgically treated patients, preoperative and postoperative tissue diagnosis corresponded in 19/20 (95%) cases, including 100% in FNA group and 91% in KHB group (P=0.999). No adverse events of tissue sampling occurred in the study.

CONCLUSIONS

Deep tissue sampling by EUS-FNA and KHB are equally effective in the diagnostics of SETs of the upper gastrointestinal tract ≥ 2 cm. However, neither EUS-FNA nor KHB provided adequate tissue sample to determine mitotic index.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT02025244).

Endoscopic ultrasonography-guided biopsy using a Franseen needle design: Initial assessment

BACKGROUND AND AIM

Recently, a 22-gauge (G) needle with a Franseen tip design was developed for endoscopic ultrasonography-guided fine-needle biopsy (EUS-FNB). The present study evaluated the performance of the Franseen biopsy needle in EUS-guided tissue acquisition.

METHODS

This is a retrospective study of patients who underwent EUS-FNB using the Franseen needle. Lesions were sampled using either the Franseen needle only or after failed diagnostic fine-needle aspiration (FNA). After rapid onsite evaluation (ROSE), two dedicated passes were carried out for histological assessment using the cell block technique. Main outcomes were: (i) rates of diagnostic adequacy for ROSE and histological diagnosis; and (ii) quality of histology as determined by total tissue area and tumor percentage in tissue.

RESULTS

Thirty patients underwent EUS-FNB of pancreatic or other masses over a 3-month period. Twenty-four lesions were sampled using the Franseen needle only and six after failed diagnostic FNA. Final diagnosis was pancreatic cancer in 12, gastrointestinal stromal cell tumor in five, other tumors in four and benign disease in nine. Diagnostic adequacy for ROSE was 96.6% and histological diagnosis was established in 96.7% of patients. Median tissue area was 2.9 mm² (IQR = 0.68-8.71 mm² ) and median tumor percentage in tissue was 73.9% (IQR = 44-97.6). Rates of technical success and adverse events were 96.7 and 3.3%, respectively.

CONCLUSION

Preliminary data suggest that the Franseen needle yields diagnostic material for ROSE and histology in >95% of patients.