Successful BRAF/MEK inhibition in a patient with BRAF V600E-mutated extrapancreatic acinar cell carcinoma

Whole genome and transcriptome analysis of pancreatic acinar cell carcinoma elucidates mechanisms of homologous recombination deficiency and unravels novel relevant fusion events

Pancreatic acinar cell carcinoma (PACC) is a rare pancreatic tumor with a heterogeneous clinical course and, except for radical surgery, limited treatment options. We present a comprehensive study encompassing whole-genome and RNA sequencing of 7 tumor samples from 3 metastatic PACC patients to further delineate its genomic landscape and potential therapeutic implications. Our findings reveal distinct signatures of homologous recombination deficiency (HRD) in patients harboring pathogenic germline BRCA1/2 and FANCL mutations, demonstrating favorable responses to poly (ADP-ribose) polymerase 1 (PARP) inhibitors with prolonged disease-free intervals. Additionally, we first describe structural variants in PACC, including BRCA1::TRIM47 fusion and another variant impacting FANCC, both events related to HRD, and we also identify alterations in the mitogen-activated protein kinase (MAPK) pathway, including RAF1 duplication as well as novel BRAF::SORBS2 and MAP7D2::SND1 gene fusions, offering potential targets for therapy. Our study underscores the importance of genome and transcriptome-wide profiling of PACC, to help guide personalized treatment strategies to improve patient outcomes.

Metastatic pancreatic cancer now in remission: a case report and literature review

Pancreatic cancer is a highly aggressive malignancy with the majority of patients presenting at a late stage with unresectable or metastatic disease. Even with first line treatment, median survival is approximately 11 months in patients with advanced PDAC. This report details the unique case of a patient that presented with peritoneal metastases from an adenocarcinoma of the body of the pancreas, had a remarkable response to palliative chemotherapy and is alive without evidence of disease 12 months following cessation of all active treatment. The initial diagnosis was 4 years ago and extensive resection of the primary was completed 2 years ago. The patient was started on standard FOLFIRINOX chemotherapy regimen, completed 6 cycles, but stopped Oxaliplatin and Irinotecan due to neuropathy and fatigue, on November 5, 2020, and transitioned to 5-fluorouracil (5-FU) and leucovorin. There was radiographic response and a notable decrease in tumor marker CA 19-9. On July 12, 2022 he underwent a multivisceral resection that included a radical anterograde modular pancreatico-splenectomy, partial gastrectomy, and splenic flexure colectomy with primary anastomosis due to tumor involvement of the posterior stomach and splenic flexure. Surgical pathology noted a moderately differentiated, grade 2 tumor staged ypT2 N0 M0. He continued the same adjuvant regimen of 5-FU and leucovorin for approximately 9 months with no new or recurrent disease on imaging. His CA 19-9 decreased within normal range after surgery and has remained within the normal limits. He remains on active surveillance. Overall, barring clear availability for targeted therapies, a metastatic PDAC of the tail may be considered to have a better prognosis than previously considered. FOLFIRINOX is the ideal treatment if the patient has a high-performance status, and PRODIGE 35 recommends 8 minimum cycles. However, in our case, the patient only tolerated 6 cycles and was still highly responsive. Despite a stage IV diagnosis, the primary tumor was resected in order to mitigate the risk for mutation and progression. Although rare, greater hope for patients with PDAC of the tail with favorable tumor biology responsive to FOLFIRINOX may contribute to increased surgical resection rates and improve survival rates.

Paediatric pancreatic acinar cell carcinoma with a novel SEC31A-BRAF fusion gene

Paediatric pancreatic acinar cell carcinoma (PACC) presents a diagnostic challenge, often confused with pancreatoblastoma (PB) due to its rarity. It is crucial to differentiate between PB and PACC, given their distinct therapeutic strategies and prognoses. Histologically, the absence of squamoid nests and scarcity of tumor mesenchyme support PACC. Conversely, the identification of a BRAF alteration leans towards PACC. Here, we present the case of an 8-year-old girl with a well-defined mass in the pancreas. The tumor exhibited a SEC31A-BRAF fusion gene and amplification of 18p, showcasing unequivocal acinar differentiation and a minor degree of neuroendocrine differentiation. Additionally, the tumor displayed scant fibrous stroma, and an absence of squamoid nests, further supporting PACC. Notably, this is the first reported instance of a solid tumor featuring a SEC31A-BRAF gene fusion. The discovery of this novel fusion gene expands our understanding of BRAF fusion partner profiles, particularly in the context of paediatric PACC.

A narrative review on rare types of pancreatic cancer: should they be treated as pancreatic ductal adenocarcinomas?

Pancreatic cancer is one of the deadliest malignancies in humans and it is expected to play a bigger part in cancer burden in the years to come. Pancreatic ductal adenocarcinoma (PDAC) represents 85% of all primary pancreatic malignancies. Recently, much attention has been given to PDAC, with significant advances in the understanding of the mechanisms underpinning disease initiation and progression, along with noticeable improvements in overall survival in both localized and metastatic settings. However, given their rarity, rare histological subtypes of pancreatic cancer have been underappreciated and are frequently treated as PDAC, even though they might present non-overlapping molecular alterations and clinical behavior. While some of these rare histological subtypes are true variants of PDAC that should be treated likewise, others represent separate clinicopathological entities, warranting a different therapeutic approach. In this review, we highlight clinical, pathological, and molecular aspects of rare histological types of pancreatic cancer, along with the currently available data to guide treatment decisions.

Exceptional Response of BRAFV600E-Mutated Acinar Cell CUP to BRAF/MEK Inhibition

Complete remission of BRAF V600E-driven ACC CUP by BRAF/MEK inhibition underscores importance of precision oncology.

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.

Near complete remission of an inoperable pancreatic acinar cell carcinoma after BRAF-/MEK-inhibitor treatment-A case report and review of the literature

INTRODUCTION

Pancreatic acinar cell carcinomas are rare malignant neoplasms. High-quality evidence about the best treatment strategy is lacking. We present the case of a 52-year-old male with a BRAFV600E -mutated PACC who experienced a complete remission after chemotherapy with BRAF-/MEK-inhibitors.

CASE

The patient presented with upper abdomen pain, night sweat, and weight loss. CT scan showed a pancreatic tumor extending from the pancreas head to body. Histological workup identified an acinar cell carcinoma. As the tumor was inoperable, chemotherapy with FOFIRNIOX was initiated and initially showed a slight regression of disease. The regimen had to be discontinued due to severe side effects. Molecular analysis identified a BRAFV600E mutation, so the patient was started on BRAF- and MEK-inhibitors (dabrafenib/trametinib). After 16 months, CT scans showed a near complete remission with a markedly improved overall health.

DISCUSSION

Studies suggest that up to one-fourth of PACCs carry a BRAF mutation and might therefore be susceptible to a BRAF-/MEK-inhibitor therapy. This offers a new therapeutic pathway to treat this rare but malignant neoplasm.

Next-generation therapies for pancreatic cancer

INTRODUCTION

Pancreas ductal adenocarcinoma (PDAC) is a frequently lethal malignancy that poses unique therapeutic challenges. The current mainstay of therapy for metastatic PDAC (mPDAC) is cytotoxic chemotherapy. NALIRIFOX (liposomal irinotecan, fluorouracil, leucovorin, oxaliplatin) is an emerging standard of care in the metastatic setting. An evolving understanding of PDAC pathogenesis is driving a shift toward targeted therapy. Olaparib, a poly-ADP-ribose polymerase (PARP) inhibitor, has regulatory approval for maintenance therapy in BRCA-mutated mPDAC along with other targeted agents receiving disease-agnostic approvals including for PDAC with rare fusions and mismatch repair deficiency. Ongoing research continues to identify and evaluate an expanding array of targeted therapies for PDAC.

AREAS COVERED

This review provides a brief overview of standard therapies for PDAC and an emphasis on current and emerging targeted therapies.

EXPERT OPINION

There is notable potential for targeted therapies for KRAS-mutated PDAC with opportunity for meaningful benefit for a sizable portion of patients with this disease. Further, emerging approaches are focused on novel immune, tumor microenvironment, and synthetic lethality strategies.

AGAP3: A novel BRAF fusion partner in pediatric pancreatic-type acinar cell carcinoma

Most available molecular data on pancreatic acinar cell carcinoma (PACC) are provided by studies of adult cases. BRAF, RAF1, or RET rearrangements have been described in approximately 30% of cases. To the best of our knowledge, only seven cases with molecular data have been reported in pediatric PACC. We report here the comprehensive study of a pancreatic-type ACC from a 6-year-old patient. We detected an AGAP3::BRAF fusion. This result showing a BRAF rearrangement demonstrates a molecular link between adult and pediatric PACC. Moreover, it identifies AGAP3, a gene located at 7q36.1 that encodes a major component of the N-methyl-d-aspartate (NMDA) receptor signaling complex, as a partner gene of BRAF. The variability of BRAF partners is consistent with a driver role of BRAF alterations in PACC. The identification of such alterations is noteworthy for considering the use of MEK inhibitors in metastatic cases. We did not detect associated genomic instability. The better outcome of pediatric cases might be related to their stable genomic background.

Vemurafenib Combined With Trametinib Significantly Benefits the Survival of a Patient With Stage IV Pancreatic Ductal Adenocarcinoma With BRAF V600E Mutation: A Case Report

Vemurafenib and trametinib have a lot of successful experiences in the treatment of unresectable or metastatic melanoma with BRAF V600E mutation. However, they have not been reported in the treatment of advanced pancreatic ductal adenocarcinoma (PDAC). We report here a 66-year-old male who was diagnosed as PDAC with multiple metastases of the abdominal cavity and liver according to pathological examination. After three cycles of gemcitabine plus nab-paclitaxel (GA) regimen chemotherapy, the liver metastasis of the patient progressed, and the patient could not continue to receive chemotherapy because of poor physical condition. BRAF V600E mutation was found by genetic detection in this patient, so targeted therapy with vemurafenib combined with trametinib was performed and the follow-up period was up to 24 months. To the best of our knowledge, this is a rare report that patients with stage IV PDAC with BRAF V600E mutation can receive significantly survival benefits from targeted therapy with vemurafenib combined with trametinib. This report provides experience for the use of these two drugs in patients with advanced PDAC.

Metastatic Acinar Cell Carcinoma of the Pancreas: A Retrospective Cohort Study on Systemic Chemotherapy and Review of the Literature

OBJECTIVES

Acinar cell carcinoma of the pancreas (pACC) forms a rare subgroup of pancreatic tumors. We report on our institutional experience with systemic first- and further-line therapy in patients with metastatic pACC and embed our findings in a review of the literature.

METHODS

Patients with stage IV pACC who started systemic treatment between 2008 and 2019 at our institution were identified via our institutional database. Clinical data were extracted from the patients' electronic data records. Survival times were calculated by the Kaplan-Meier method.

RESULTS

Six patients received a fluoropyrimidine- and oxaliplatin-containing first-line treatment, and 4 patients were started on gemcitabine-based protocols. Median progression-free survival was 4.8 months [95% confidence interval (CI), 3.3 to not available (n.a.)], and median overall survival was 15.3 months (95% CI, 10.1 to n.a.). Residual survival for second-line treatment was 2.1 months (95% CI, 1.3 to n.a.), although 1 patient experienced almost complete remission under targeted therapy.

CONCLUSIONS

The most encouraging and deep responses result from poly-chemotherapy with leucovorin, 5-fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX), which seems to be the appropriate choice in fit patients. Gemcitabine monotherapy seems without substantial activity in pACC. Whenever possible, patients with pACC should be screened for targetable mutations.

Pancreatic adenocarcinoma: molecular drivers and the role of targeted therapy

Prognosis from pancreatic ductal adenocarcinoma (PDAC) continues to be poor despite the many efforts channeled to improve its management. Although the mainstay treatment is still traditional chemotherapy, recent advances highlighted a promising potential for targeted therapy in the management of this disease. Those advances emphasize the significance of timely genomic profiling of tumor tissue as well as germline testing of patients to identify potential markers of targeted therapy. While targeted therapy is reserved for a relatively small subset of patients with PDAC, ongoing research is uncovering additional markers, and targeted agents, that will hopefully translate to better outcomes for patients.