The Molecular Landscape of Pancreatobiliary Cancers for Novel Targeted Therapies From Real-World Genomic Profiling

Long-term survival after systemic chemotherapy, chemoradiotherapy, and maintenance therapy for an older adult patient with recurrent pancreatic acinar cell carcinoma

Pancreatic acinar cell carcinoma (PACC) is a rare cancer with no specific treatment. The treatment and chemotherapy for PACC are selected according to pancreatic ductal adenocarcinoma (PDAC). Herein, we describe a recurrent PACC case of an older adult patient. The patient was treated with systemic chemotherapy, chemoradiotherapy, and maintenance therapy based on the pathologic germline BRCA2 variant, resulting in long-term survival. The pathogenic BRCA variant is detected more frequently in patients with PACC than in those with PDAC. The BRCA variant significantly impacts treatment selection and prognosis; therefore, early genomic analysis is recommended when treating PACC.

Oil blotting paper for formalin fixation increases endoscopic ultrasound-guided tissue acquisition-collected sample volumes on glass slides

OBJECTIVES

Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is used for pathological diagnosis and obtaining samples for molecular testing, facilitating the initiation of targeted therapies in patients with pancreatic cancer. However, samples obtained via EUS-TA are often insufficient, requiring more efforts to improve sampling adequacy for molecular testing. Therefore, this study investigated the use of oil blotting paper for formalin fixation of samples obtained via EUS-TA.

METHODS

This prospective study enrolled 42 patients who underwent EUS-TA for pancreatic cancer between September 2020 and February 2022 at the Osaka International Cancer Institute. After a portion of each sample obtained via EUS-TA was separated for routine histological evaluation, the residual samples were divided into filter paper and oil blotting paper groups for analysis. Accordingly, filter paper and oil blotting paper were used for the formalin fixation process. The total tissue, nuclear, and cytoplasm areas of each sample were quantitatively evaluated using virtual slides, and the specimen volume and histological diagnosis of each sample were evaluated by an expert pathologist.

RESULTS

All cases were cytologically diagnosed as adenocarcinoma. The area ratios of the total tissue, nuclear, and cytoplasmic portions were significantly larger in the oil blotting paper group than in the filter paper group. The frequency of cases with large amount of tumor cells was significantly higher in the oil blotting paper group (33.3%) than in the filter paper group (11.9%) (p = 0.035).

CONCLUSIONS

Oil blotting paper can increase the sample volume obtained via EUS-TA on glass slides and improve sampling adequacy for molecular testing.

An approach for improvement of the accuracy of cancer gene panel testing

BACKGROUND

Tissue-based comprehensive genomic profiling (CGP) is increasingly being employed for genotype-directed therapies in patients with advanced cancer. However, tissue availability may limit their potential applications. In Japan, the cost of cancer gene panel tests is covered by public insurance for patients diagnosed with advanced solid tumors once in their lifetime. Therefore, it is essential to improve the success rate (reportability) and accuracy of CGP tests. The purpose of this study was to identify the factors associated with efficient and accurate CGP testing using relevant information obtained from real-world data.

METHODS

This study included 159 samples analyzed using tumor-only panel FoundationOne® CDx cancer genome profiling (F1CDx) and 85 samples analyzed using matched-pair panel OncoGuide™ NCC Oncopanel system (NCCOP) at St. Marianna University Hospital. Sample characteristics (fixation conditions, storage period, histology, tumor cell ratio, and genomic tumor cell content), CGP performance, and quality control status were evaluated across all 244 tested samples.

RESULTS

In 237/244 samples (97.1%), CGP testing results were successfully obtained [F1CDx, 99.4% (158/159) and NCCOP, 92.9% (79/85)]. An increased number of fibroblasts, inflammatory cells, and necrotic tumor cells, long-term storage, and/or prolonged fixation of tissue sections were involved in the unreported results and/or qualified CGP results. In addition, a negative correlation between median insert size values and ΔΔCq was observed in the NCCOP system.

CONCLUSION

We identified various factors associated with efficient and accurate CGP testing using relevant information obtained from real-world data, suggesting that thorough selection and preparation of tissue sections could optimize CGP and maximize useful information.

The Molecular Landscape of Gastric Cancers for Novel Targeted Therapies from Real-World Genomic Profiling

BACKGROUND

Panel-based comprehensive genomic profiling is used in clinical practice worldwide; however, large real-world datasets of patients with advanced gastric cancer are not well known.

OBJECTIVE

We investigated what differences exist in clinically relevant alterations for molecularly defined or age-stratified subgroups.

METHODS

This was a collaborative biomarker study of a real-world dataset from comprehensive genomic profiling testing (Foundation Medicine, Inc.). Hybrid capture was carried out on at least 324 cancer-related genes and select introns from 31 genes frequently rearranged in cancer. Overall, 4634 patients were available for analyses and were stratified by age (≥ 40/< 40 years), microsatellite instability status, tumor mutational burden status (high 10 ≥ /low < 10 Muts/Mb), Epstein-Barr virus status, and select gene alterations. We analyzed the frequency of alterations with a chi-square test with Yate's correction.

RESULTS

Genes with frequent alterations included TP53 (60.1%), ARID1A (19.6%), CDKN2A (18.2%), KRAS (16.6%), and CDH1 (15.8%). Differences in comprehensive genomic profiling were observed according to molecularly defined or age-stratified subgroups. Druggable genomic alterations were detected in 31.4% of patients; ATM (4.4%), BRAF V600E (0.4%), BRCA1 (1.5%), BRCA2 (2.9%), ERBB2 amplification (9.2%), IDH1 (0.2%), KRAS G12C (0.7%), microsatellite instability-high (4.8%), NTRK1/2/3 fusion (0.13%), PIK3CA mutation (11.4%), and tumor mutational burden-high (9.4%). CDH1 alterations and MET amplification were significantly more frequent in patients aged < 40 years (27.7 and 6.2%) than in those aged ≥ 40 years (14.7 and 4.0%).

CONCLUSIONS

Real-world datasets from clinical panel testing revealed the genomic landscape in gastric cancer by subgroup. These findings provide insights for the current therapeutic strategies and future development of treatments in gastric cancer.

Comprehensive review of pancreatic acinar cell carcinoma: epidemiology, diagnosis, molecular features and treatment

Pancreatic acinar cell carcinoma is a rare form (0.2-4.3%) of pancreatic neoplasm with unique clinical and molecular characteristics, which largely differ from pancreatic ductal adenocarcinoma. Pancreatic acinar cell carcinoma occurs more frequently in males and can occur in children. Serum lipase is elevated in 24-58% of patients with pancreatic acinar cell carcinoma. Pancreatic acinar cell carcinomas tend to be large at diagnosis (median tumour size: ~5 cm) and are frequently located in the pancreas head. Radiologically, pancreatic acinar cell carcinoma generally exhibits a solid appearance; however, necrosis, cystic changes and intratumoral haemorrhage can occur in larger lesions. Immunostaining is essential for the definitive diagnosis of pancreatic acinar cell carcinoma. Compared with pancreatic ductal adenocarcinoma, pancreatic acinar cell carcinoma has a more favourable prognosis. Although radical surgery is recommended for patients with pancreatic acinar cell carcinoma who do not have distant metastases, the recurrence rate is high. The effectiveness of adjuvant therapy for pancreatic acinar cell carcinoma is unclear. The response to FOLFIRINOX is generally favourable, and some patients achieve a complete response. Pancreatic acinar cell carcinoma has a different genomic profile compared with pancreatic ductal adenocarcinoma. Although genomic analyses have shown that pancreatic acinar cell carcinoma rarely has KRAS, TP53 and CDKN2A mutations, it has a higher prevalence of homologous recombination-related genes, including BRCA1/2 and ATM, than pancreatic ductal adenocarcinoma, suggesting high sensitivity to platinum-containing regimens and PARP inhibitors. Targeted therapies for genomic alternations are beneficial. Therefore, genetic testing is important for patients with pancreatic acinar cell carcinoma to choose the optimal therapeutic strategy.

Current Status of Targeted Therapy for Biliary Tract Cancer in the Era of Precision Medicine

First-line chemotherapy has been established for advanced biliary tract cancer (BTC). However, few treatment options are available as second-line treatment. Advances in comprehensive genomic analysis revealed that nearly half of patients with BTC harbor targetable genetic alterations such as fibroblast growth factor receptor (FGFR), isocitrate dehydrogenase (IDH), BRAF, human epidermal growth factor receptor 2 (HER2), microsatellite instability (MSI)-high, neurotrophic tropomyosin receptor kinase (NTRK), rearranged during transfection (RET), and poly (adenosine diphosphate-ribose) polymerase (PARP). This review summarizes currently available options in precision medicine and clinical trials for patients with advanced BTC.

Genomic profile and clinical features of MSI-H and TMB-high pancreatic cancers: real-world data from C-CAT database

BACKGROUND

Microsatellite instability high (MSI-H) and tumor mutational burden high (TMB-high) pancreatic cancer are rare, and information is lacking. Based on the C-CAT database, we analyzed the clinical and genomic characteristics of patients with these subtypes.

METHODS

We retrospectively reviewed data on 2206 patients with unresectable pancreatic adenocarcinoma enrolled in C-CAT between July 2019 and January 2022. The clinical features, proportion of genomic variants classified as oncogenic/pathogenic in C-CAT, overall response rate (ORR), disease control rate (DCR), and time to treatment failure (TTF) of chemotherapy as first-line treatment were evaluated.

RESULTS

Numbers of patients with MSI-H and TMB-high were 7 (0.3%) and 39 (1.8%), respectively. All MSI-H patients were TMB-high. MSI-H and TMB-high patients harbored more mismatch repair genes, such as MSH2, homologous recombination-related genes, such as ATR and BRCA2, and other genes including BRAF, KMT2D, and SMARCA4. None of the 6 MSI-H patients who received chemotherapy achieved a clinical response, including 4 patients treated with gemcitabine plus nab-paclitaxel (GnP) therapy, whose DCR was significantly lower than that of microsatellite stable (MSS) patients (0 vs. 67.0%, respectively, p = 0.01). Among the TMB-high and TMB-low groups, no significant differences were shown in ORR, DCR (17.1 vs. 23.1% and 57.1 vs. 63.1%, respectively), or median TTF (25.9 vs. 28.0 weeks, respectively) of overall first-line chemotherapy.

CONCLUSIONS

MSI-H and TMB-high pancreatic cancers showed some distinct genomic and clinical features from our real-world data. These results suggest the importance of adapting optimal treatment strategies according to the genomic alterations.

Current status and issues in genomic analysis using EUS-FNA/FNB specimens in hepatobiliary-pancreatic cancers

Comprehensive genomic profiling based on next-generation sequencing has recently been used to provide precision medicine for various advanced cancers. Endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA) and EUS-guided fine-needle biopsy (EUS-FNB) play essential roles in the diagnosis of abdominal masses, mainly pancreatic cancers. In recent years, CGP analysis using EUS-FNA/FNB specimens for hepatobiliary-pancreatic cancers has increased; however, the success rate of CGP analysis is not clinically satisfactory, and many issues need to be resolved to improve the success rate of CGP analysis. In this article, we review the transition from EUS-FNA to FNB, compare each test, and discuss the current status and issues in genomic analysis of hepatobiliary-pancreatic cancers using EUS-FNA/FNB specimens.

Smaller panel, similar results: genomic profiling and molecularly informed therapy in pancreatic cancer

BACKGROUND

Pancreatic cancer has a dismal prognosis. One reason is resistance to cytotoxic drugs. Molecularly matched therapies might overcome this resistance but the best approach to identify those patients who may benefit is unknown. Therefore, we sought to evaluate a molecularly guided treatment approach.

MATERIALS AND METHODS

We retrospectively analyzed the clinical outcome and mutational status of patients with pancreatic cancer who received molecular profiling at the West German Cancer Center Essen from 2016 to 2021. We carried out a 47-gene DNA next-generation sequencing (NGS) panel. Furthermore, we assessed microsatellite instability-high/deficient mismatch repair (MSI-H/dMMR) status and, sequentially and only in case of KRAS wild-type, gene fusions via RNA-based NGS. Patient data and treatment were retrieved from the electronic medical records.

RESULTS

Of 190 included patients, 171 had pancreatic ductal adenocarcinoma (90%). One hundred and three patients had stage IV pancreatic cancer at diagnosis (54%). MMR analysis in 94 patients (94/190, 49.5%) identified 3 patients with dMMR (3/94, 3.2%). Notably, we identified 32 patients with KRAS wild-type status (16.8%). To identify driver alterations in these patients, we conducted an RNA-based fusion assay on 13 assessable samples and identified 5 potentially actionable fusions (5/13, 38.5%). Overall, we identified 34 patients with potentially actionable alterations (34/190, 17.9%). Of these 34 patients, 10 patients (10/34, 29.4%) finally received at least one molecularly targeted treatment and 4 patients had an exceptional response (>9 months on treatment).

CONCLUSIONS

Here, we show that a small-sized gene panel can suffice to identify relevant therapeutic options for pancreatic cancer patients. Informally comparing with previous large-scale studies, this approach yields a similar detection rate of actionable targets. We propose molecular sequencing of pancreatic cancer as standard of care to identify KRAS wild-type and rare molecular subsets for targeted treatment strategies.