The Italian Rare Biliary tract Cancer initiative (IRaBiCa): A multicentric observational study of Gruppo Oncologico dell'Italia Meridionale (GOIM) in collaboration with Gruppo Italiano Colangiocarcinoma (GICO)

INTRODUCTION

About 90% of cholangiocarcinomas are adenocarcinomas with glandular or tubular structures lined by epithelial cells, with no bile production and with a variable degree of differentiation, arising in the background of desmoplastic stroma. The remaining 10% is represented by rarer histological variants of which there is little knowledge regarding the biological behavior, molecular characterization, and sensitivity to the various possible therapies, including molecular-based treatments. Such rare tumors are described only in case reports or small retrospective series because of their exclusion from clinical trials. This national initiative, here presented, aims to address the following knowledge gap: a) how much does histological diversity translate into clinical manifestation variety? b) are those chemotherapy regimens, recommended for conventional biliary tract cancers, potentially active in rare variants?Therefore, epidemiological, pathological, and clinical characterization of series of rare biliary histotypes/variants, for which therapeutic and follow-up data are available, will be collected.

METHODS

An Italian task force on rare tumors of the biliary tract (IRaBiCa) has been created, whose initiative is a multicenter retrospective study involving 34 Italian cancer centers.Clinical data from approximately 100 patients will be collected and analyzed. Continuous variables will be presented as median ± standard deviation, while categorical variables will be expressed in terms of frequency. Kaplan-Maier analyses will be used to compare disease free, progression free and overall survival, according to the different histotypes.

CONCLUSIONS

We expect to gather novel data on rare histotypes of biliary tract cancer that will be useful to support their molecular and immunological characterization.

Metastatic malignant melanoma to the gallbladder. Case report and review of the literature

Solitary metastasis of malignant melanoma (MM) to the gallbladder (GB) is rare and generally originates from skin melanoma. MM is a neoplasm with an often unpredictable course and metastases can potentially affecting all organs. The occurrence of metastasis in the GB is unusual and has only been exceptionally reported in the literature. We describe a case of an 86-year-old man with an isolated MM metastasis located within the GB presenting with symptoms mimicking acute cholecystitis. Anamnestically, he presented a history of malignant melanoma (Clark level III) resected from his left leg 17 years ago. Furthermore we provide a review of the literature with a focus on diagnostic clues to distinguish between primary versus secondary GB MMs and on the best surgical management that should be used.

Positive Lymph Nodes Independently Affect Long-Term Survival After Pancreaticoduodenectomy for Non-Ampullary Duodenal Adenocarcinoma: A Single-Center, Retrospective Analysis

Background/Objectives: The main treatment for non-ampullary duodenal adenocarcinoma (NDA) is pancreatoduodenectomy (PD) with lymphadenectomy (LN). Several studies have proposed a minimum number of examined lymph nodes (MNELN) to ensure proper staging. This study investigated the impact of nodal parameters-including the pattern of nodal spread-on oncologic outcomes following PD for NDA. Furthermore, we sought to determine the MNELN to ensure reliable detection of nodal involvement. Methods: This was a single-center, retrospective study. Consecutive patients who underwent PD from 2000 to 2019 with a final diagnosis of NDA were retrieved from a prospectively maintained database. The probability of detecting at least one metastatic LN in a node-positive patient was assessed using a model based on the binomial probability law. Results: A total of 70 patients met the inclusion criteria. The median number of ELNs was 35 (22-43, IQR). Thirty-six patients (51%) had at least one PLN. A node-positive disease was associated with adverse pathologic features, including high tumor grade and perineural and peripancreatic fat invasion. This translated into a greater recurrence rate (p < 0.001). The MNELN yielding a 95% probability of detecting at least one metastatic node in a node-positive patient was 25. After a median follow-up of 73 months, the median recurrence-free survival (RFS) was 33 months (95% CI 13-97), and the overall survival (OS) was 41 months (95% CI 17-96). The LN ratio, tumor grade, and metastases at stations 8 and 12 were independently associated with OS (p < 0.05). Conclusions: Nodal metastases are common among patients with NDA and have a considerable impact on long-term survival. Stations 8 and 12 were associated with OS. Therefore, an adequate lymphadenectomy, possibly including stations 8 and 12, is recommended in patients with NDA.

Claudin 18.2: a promising actionable target in biliary tract cancers

BACKGROUND AND PURPOSE

Anti-claudin 18.2 (anti-CLDN18.2) therapy has been approved for patients with CLDN18-positive gastric and gastroesophageal junction adenocarcinomas. The current study aims at evaluating the expression of CLDN18 in a large cohort of pathologically characterized biliary tract cancers (BTCs).

MATERIALS AND METHODS

A series of 237 BTCs were collected and reviewed under the BITCOIN protocol. All samples were assessed for CLDN18 status using immunohistochemistry (clone 43-14A). Tumor positivity for CLDN18 was determined if ≥75% of tumor cells exhibited moderate-to-strong membranous staining.

RESULTS

CLDN18 expression was found in 29.5% of BTCs (70/237), with the highest rates in gallbladder carcinoma (GBC; 62.5%; 20/32) and extrahepatic cholangiocarcinoma (eCCA; 53.4%; 31/58), compared with intrahepatic cholangiocarcinoma (iCCA; 12.9%; 19/147) (P < 0.0001). CLDN18 positivity was detected in 5.5% of cases (13/237), most common in GBC (15.6%; 5/32), followed by eCCAs (8.6%; 5/58) and iCCAs (2.0%; 3/147) (P = 0.0045). Most CLDN18-positive samples (10/13) exhibited a heterogenous staining pattern. In iCCAs, large duct subtypes had higher CLDN18 expression [33.3% (10/30) versus 7.7% (9/117), P = 0.0002] and positivity [6.7% (2/30) versus 0.9% (1/117), P = 0.106] than small duct iCCAs. No significant differences were observed across GBC and eCCA histotypes, and CLDN18 was not associated with IDH1 or FGFR2 status in iCCAs.

CONCLUSIONS

This study demonstrates that CLDN18 expression is present in a subset of BTCs, with significantly higher positivity rates in GBCs and eCCAs compared with iCCAs. In iCCAs, CLDN18 expression was more frequent in the large duct subtype but was not associated with IDH1 or FGFR2 status. These findings suggest that CLDN18 could be a potential therapeutic target in BTCs, warranting further prospective studies to evaluate its clinical significance and impact on patient outcomes.

Clinical Relevance of ATRX/DAXX Gene Mutations and ALT in Functioning Pancreatic Neuroendocrine Tumors

Functioning pancreatic neuroendocrine tumors (PanNETs) represent a subset of PanNETs that cause symptoms due to hormonal activity. Insulinoma is the most common functioning PanNET type. Mutations in the alpha thalassemia/mental retardation X-linked (ATRX) and death domain-associated protein (DAXX) genes result in genomic instability. ATRX/DAXX mutations and associated alternative lengthening of telomeres (ALT) are common in non-functioning PanNETs and associated with aggressive tumor behavior. Recent reports have shown that ATRX/DAXX mutations and ALT are also present in functioning PanNETs. In this review, we summarize the literature addressing ATRX/DAXX mutations and ALT in functioning PanNETs and discuss the clinical relevance with regard to distinguishing aggressive and indolent functioning tumors. ATRX/DAXX gene mutations and/or ALT have been reported in insulinoma, glucagonoma, gastrinoma, VIPoma and calcitoninoma. In insulinoma, the presence of ATRX/DAXX mutations and ALT are associated with aggressive behavior and could therefore be used as prognostic biomarkers. Although ATRX/DAXX mutation and ALT assessment may currently not be the standard of care in routine diagnostic pathology practice, the use of DAXX/ATRX immunohistochemistry at least can be encouraged not only for non-functioning but also for functioning PanNETs.

Genomic Profiling of Rare Undifferentiated Sarcomatoid Subtypes of Pancreatic Carcinomas: In Search of Therapeutic Targets

PURPOSE

The highly aggressive undifferentiated sarcomatoid carcinoma (USC) subtype of pancreatic ductal adenocarcinoma (PDAC) remains poorly characterized because of its rarity. Previous case reports suggest that immune checkpoint inhibitors could be a promising treatment strategy, but the prevalence of established predictive biomarkers of response is largely unknown. The objective of this study was to leverage comprehensive genomic profiling of USC PDAC tumors to determine the prevalence of biomarkers associated with potential response to targeted therapies.

METHODS

USC tumors (n = 20) underwent central pathology review by a board-certified gastrointestinal pathologist to confirm the diagnosis. These samples were compared with non-USC PDAC tumors (N = 5,562). Retrospective analysis of DNA and RNA next-generation sequencing data was performed.

RESULTS

USC PDACs were more frequently PD-L1+ by immunohistochemistry than non-USC PDAC (63% v 16%, respectively, P < .001). Furthermore, USC PDAC had an increase in neutrophils (8.99% v 5.55%, P = .005) and dendritic cells (1.08% v 0.00%, q = 0.022) and an increased expression of PDCD1LG2 (4.6% v 1.3%, q = 0.001), PDCD1 (2.0% v 0.8%, q = 0.060), and HAVCR2 (45.9% v 21.7%, q = 0.107) than non-USC PDAC. Similar to non-USC PDAC, KRAS was the most commonly mutated gene (86% v 90%, respectively, P = 1).

CONCLUSION

To our knowledge, this work represents the largest molecular analysis of USC tumors to date and showed an increased expression of immune checkpoint genes in USC tumors. These findings provide evidence for further investigation into immune checkpoint inhibitors in USC tumors.

Surgery for pancreatic neuroendocrine tumors during the COVID-19 pandemic: a retrospective cohort from a high-volume center

During the COVID-19 pandemic, pancreatic surgery for pancreatic neuroendocrine tumors (PNETs) with surgical indications was postponed or canceled. Patients with PNET patients who underwent pancreatic surgery during the COVID-19 restriction period (3 years) were compared with a similar cohort of patients who underwent surgery in the previous 3 years. Data on patients' characteristics, waiting time, and surgical and pathology outcomes were evaluated. During the study period, 370 patients received surgery for PNETs, 205 (55%) during the first period, and 165 (45%) during the pandemic. A lengthening of the waiting list (182 [IQR 100-357] vs. 60 [40-88] days, p < 0.001) and increased use of anti-tumor medical treatments (any therapy, peptide receptor radionuclide therapy, and somatostatin analogs; all p < 0.001) was found. During the pandemic, surgery occurred after a median of 381 days [IQR 200-610] from diagnosis (vs. 103 [IQR 52-192] of the pre-COVID-19 period, p < 0.001). No statistically significant differences in tumor size and grading distribution were found between the two periods (both p > 0.05), yet only a modest increase of the median Ki67 values in cases operated during the pandemic (4% vs. 3%, p = 0.03). Lastly, these latter patients experienced less major postoperative complications (13% vs. 24%, p = 0.007). During COVID-19, the surgical waiting list of PNET patients was drastically extended, and bridge therapies were preferred. This did not result in more advanced cases at final pathology. PRRT and SSA are valid alternative therapies for PNETs when surgery is not feasible.

Neoplastic Progression in Neuroendocrine Neoplasms of the Pancreas

CONTEXT.—

Pancreatic neuroendocrine neoplasms (PanNENs) represent a heterogeneous group of epithelial tumors of the pancreas showing neuroendocrine differentiation. These neoplasms are classified into well-differentiated pancreatic neuroendocrine tumors (PanNETs), which include G1, G2, and G3 tumors, and poorly differentiated pancreatic neuroendocrine carcinomas (PanNECs), which are G3 by definition. This classification mirrors clinical, histologic, and behavioral differences and is also supported by robust molecular evidence.

OBJECTIVE.—

To summarize and discuss the state of the art regarding neoplastic progression of PanNENs. A better comprehension of the mechanisms underpinning neoplastic evolution and progression of these neoplasms may open new horizons for expanding biologic knowledge and ultimately for addressing new therapeutic strategies for patients with PanNENs.

DATA SOURCES.—

Literature review of published studies and the authors' own work.

CONCLUSIONS.—

PanNETs can be seen as a unique category, where G1-G2 tumors may progress to G3 tumors mainly driven by DAXX/ATRX mutations and alternative lengthening of telomeres. Conversely, PanNECs display totally different histomolecular features more closely related to pancreatic ductal adenocarcinoma, including TP53 and Rb alterations. They seem to derive from a nonneuroendocrine cell of origin. Even the study of PanNEN precursor lesions corroborates the rationale of considering PanNETs and PanNECs as separate and distinct entities. Improving the knowledge regarding this dichotomous distinction, which guides tumor evolution and progression, will represent a critical basis for PanNEN precision oncology.

Genomic determinants of biological aggressiveness and poor prognosis of pancreatic cancers: KRAS and beyond

INTRODUCTION

A marked histomolecular heterogeneity characterizes pancreatic cancer. Thus, different tumor histologies with divergent genomic profiles exist within the same category.

AREAS COVERED

Using data from PubMed, SCOPUS, and Embase (last search date: 04/04/2024), this expert-based, narrative review presents and discusses the essential molecular determinants of biological aggressiveness and poor prognosis in pancreatic cancer. First, KRAS mutation still represents one of the most critical difficulties in treating pancreatic cancers. In this district, it is mutated in > 90% of malignant tumors. Notably, actionable alterations for molecular-based therapies are typically lacking in KRAS-mutated pancreatic cancer. Furthermore, transcriptome-based studies clarified that the squamous phenotype is characterized by poorer prognosis and response to standard chemotherapy. We also discuss molecular biomarkers related to dismal prognosis in specific subsets of pancreatic cancer, such as SMAD4 in signet-ring cell carcinoma and TP53 in invasive cancers derived from intraductal tubulopapillary neoplasms.

EXPERT OPINION

The identification of the subgroups of pancreatic cancer with particularly unfavorable prognoses is a critical step for addressing specific research efforts. In addition to implementing and strengthening current precision oncology strategies, the decisive step for improving the survival of patients affected by pancreatic cancer must pass through targeting the KRAS gene.

Morphological and molecular characterization of colorectal sessile serrated lesions with dysplasia

In sessile serrated lesions (SSLs) with adenomatous dysplasia, the dysplastic component and the serrated component without dysplasia should be considered as part of the same lesion, classified as SSL with dysplasia. However, some of these lesions may actually represent collisions between a serrated polyp and a conventional adenoma. Further supporting the "collision theory", conventional adenomatous dysplasia may be found in association with hyperplastic polyps (HPs). In order to determine the molecular and biological landscape of conventional type dysplasia in serrated lesions, we collected 17 cases of colorectal serrated lesions with adenomatous dysplasia, classifying them as SSL with dysplasia (n = 10) or as mixed lesions comprising a HP component and a conventional adenomatous component (n = 7). We characterized the dysplastic and the non-dysplastic component of each lesion, after microdissection, through the targeted mutational analysis of 11 commonly altered genes in colorectal cancer (AKT1, APC, BRAF, CTNNB1, KIT, KRAS, NRAS, PDGFRA, PIK3CA, PTEN and TP53). We also characterized MMR and p53 status by immunohistochemistry. Overall, 14/17 (82.4 %) cases harbored a mutation in at least one of the two components. The most altered genes were BRAF in 10/17 (58.8 %) cases, APC in 2/17 (11.8 %) and TP53 in 4/17 (23.5 %). Among the SSL with dysplasia, the mutational profile was concordant between the two components in 7/10 (70 %) cases, while among the mixed lesions, the mutational profile was concordant in 1/7 (14.3 %). In all but two cases of SSL with dysplasia, MMR status was concordant between the two components of the serrated lesions. Our findings suggest that adenomatous dysplasia may develop in SSL as part of the serrated lesion, even if some SSL with dysplasia may actually be collision lesions. On the other hand, the polyps that are morphologically classifiable as mixed lesions composed of a HP and a conventional adenomatous component are more likely to be collision lesions.

Spliceosomic dysregulation in pancreatic cancer uncovers splicing factors PRPF8 and RBMX as novel candidate actionable targets

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer, characterized by late diagnosis and poor treatment response. Surgery is the only curative approach, only available to early-diagnosed patients. Current therapies have limited effects, cause severe toxicities, and minimally improve overall survival. Understanding of splicing machinery alterations in PDAC remains incomplete. Here, we comprehensively examined 59 splicing machinery components, uncovering dysregulation in pre-mRNA processing factor 8 (PRPF8) and RNA-binding motif protein X-linked (RBMX). Their downregulated expression was linked to poor prognosis and malignancy features, including tumor stage, invasion and metastasis, and associated with poorer survival and the mutation of key PDAC genes. Experimental modulation of these splicing factors in pancreatic cancer cell lines reverted their expression to non-tumor levels and resulted in decreased key tumor-related features. These results provide evidence that the splicing machinery is altered in PDAC, wherein PRPF8 and RBMX emerge as candidate actionable therapeutic targets.

Subgrading of G2 Pancreatic Neuroendocrine Tumors as 2A (Ki67 3% to < 10%) Versus 2B (10% to ≤ 20%) Identifies Behaviorally Distinct Subsets in Keeping with the Evolving Management Protocols

BACKGROUND

Grade 1/2 PanNETs are mostly managed similarly, typically without any adjunct treatment with the belief that their overall metastasis rate is low. In oncology literature, Ki67-index of 10% is increasingly being used as the cutoff in stratifying patients to different protocols, although there are no systematic pathology-based studies supporting this approach.

METHODS

Ki67-index was correlated with clinicopathologic parameters in 190 resected PanNETs. A validation cohort (n = 145) was separately analyzed.

RESULTS

In initial cohort, maximally selected rank statistics method revealed 12% to be the discriminatory cutoff (close to 10% rule of thumb). G2b cases had liver/distant metastasis rate of almost threefold higher than that of G2a and showed significantly higher frequency of all histopathologic signs of aggressiveness (tumor size, perineural/vascular invasion, infiltrative growth pattern, lymph node metastasis). In validation cohort, these figures were as striking. When all cases were analyzed together, compared with G1, the G2b category had nine times higher liver/distant metastasis rate (6.1 vs. 58.5%; p < 0.001) and three times higher lymph node metastasis rate (20.5 vs. 65.1%; p < 0.001).

CONCLUSIONS

G2b PanNETs act very similar to G3, supporting management protocols that regard them as potential therapy candidates. Concerning local management, metastatic behavior in G2b cases indicate they may not be as amenable for conservative approaches, such as watchful waiting or enucleation. This substaging should be considered into diagnostic guidelines, and clinical trials need to be devised to determine the more appropriate management protocols for G2b (10% to ≤ 20%) group, which shows liver/distant metastasis in more than half of the cases, which at minimum warrants closer follow-up.

Potentialities and critical issues of liquid biopsy in clinical practice: An umbrella review

BACKGROUND

Liquid biopsy (LB) is a laboratory test performed on a fluid sample aiming at analyzing molecular data derived from circulating cells and related entities, or from nucleic acids. This umbrella review aims to map and evaluate the evidence supporting the use of LB in medicine across different medical specialities and conditions.

METHODS

We searched three repositories from database inception up to October 1, 2023 and we included meta-analyses of observational studies reporting data on the use of LB, compared to gold standard, and its accuracy (area under the curve, AUC).

RESULTS

Among 726 articles initially screened, 42 systematic reviews were included. Most of the outcomes explored (202/211) were related to cancer. We found that 75/211 had an excellent accuracy (AUC >0.90), with one comparison with an AUC equal to 1, i.e., Cell-Free Human Papillomavirus DNA (cfHPV-DNA) for HPV-positive oropharyngeal squamous cell carcinoma. However, considering published meta-analyses, all the outcomes were graded as very low on the GRADE criteria, and the heterogeneity was never reported.

DISCUSSION

The literature about LB is rapidly increasing and some promising data about precision oncology are now available. However, this umbrella review on existing meta-analyses highlighted some critical issues for providing quantitative estimations on the different roles of LB.

SWI/SNF Complex-Deficient Undifferentiated Carcinoma of the Pancreas: Clinicopathologic and Genomic Analysis

Inactivating alterations in the SWItch/Sucrose NonFermentable (SWI/SNF) Chromatin Remodeling Complex subunits have been described in multiple tumor types. Recent studies focused on SMARC subunits of this complex to understand their relationship with tumor characteristics and therapeutic opportunities. To date, pancreatic cancer with these alterations has not been well studied, although isolated cases of undifferentiated carcinomas have been reported. Herein, we screened 59 pancreatic undifferentiated carcinomas for alterations in SWI/SNF complex-related (SMARCB1 [BAF47/INI1], SMARCA4 [BRG1], SMARCA2 [BRM]) proteins and/or genes using immunohistochemistry and/or next-generation sequencing. Cases with alterations in SWI/SNF complex-related proteins/genes were compared with cases without alterations, as well as with 96 conventional pancreatic ductal adenocarcinomas (PDAC). In all tumor groups, mismatch repair and PD-L1 protein expression were also evaluated. Thirty of 59 (51%) undifferentiated carcinomas had a loss of SWI/SNF complex-related protein expression or gene alteration. Twenty-seven of 30 (90%) SWI-/SNF-deficient undifferentiated carcinomas had rhabdoid morphology (vs 9/29 [31%] SWI-/SNF-retained undifferentiated carcinomas; P < .001) and all expressed cytokeratin, at least focally. Immunohistochemically, SMARCB1 protein expression was absent in 16/30 (53%) cases, SMARCA2 in 4/30 (13%), and SMARCA4 in 4/30 (13%); both SMARCB1 and SMARCA2 protein expressions were absent in 1/30 (3%). Five of 8 (62.5%) SWI-/SNF-deficient undifferentiated carcinomas that displayed loss of SMARCB1 protein expression by immunohistochemistry were found to have corresponding SMARCB1 deletions by next-generation sequencing. Analysis of canonical driver mutations for PDAC in these cases showed KRAS (2/5) and TP53 (2/5) abnormalities. Median combined positive score for PD-L1 (E1L3N) was significantly higher in the undifferentiated carcinomas with/without SWI/SNF deficiency compared with the conventional PDACs (P < .001). SWI-/SNF-deficient undifferentiated carcinomas were larger (P < .001) and occurred in younger patients (P < .001). Patients with SWI-/SNF-deficient undifferentiated carcinoma had worse overall survival compared with patients with SWI-/SNF-retained undifferentiated carcinoma (P = .004) and PDAC (P < .001). Our findings demonstrate that SWI-/SNF-deficient pancreatic undifferentiated carcinomas are frequently characterized by rhabdoid morphology, exhibit highly aggressive behavior, and have a negative prognostic impact. The ones with SMARCB1 deletions appear to be frequently KRAS wild type. Innovative developmental therapeutic strategies targeting this genomic basis of the SWI/SNF complex and the therapeutic implications of EZH2 inhibition (NCT03213665), SMARCA2 degrader (NCT05639751), or immunotherapy are currently under investigation.