Precision Oncology in Surgery: Patient Selection for Operable Pancreatic Cancer.

OBJECTIVE: We aimed to define preoperative clinical and molecular characteristics that would allow better patient selection for operative resection. BACKGROUND: Although we use molecular selection methods for systemic targeted therapies, these principles are not applied to surgical oncology. Improving patient selection is of vital importance for the operative treatment of pancreatic cancer (pancreatic ductal adenocarcinoma). Although surgery is the only chance of long-term survival, 80% still succumb to the disease and approximately 30% die within 1 year, often sooner than those that have unresected local disease. METHOD: In 3 independent pancreatic ductal adenocarcinoma cohorts (total participants = 1184) the relationship between aberrant expression of prometastatic proteins S100A2 and S100A4 and survival was assessed. A preoperative nomogram based on clinical variables available before surgery and expression of these proteins was constructed and compared to traditional measures, and a postoperative nomogram. RESULTS: High expression of either S100A2 or S100A4 was independent poor prognostic factors in a training cohort of 518 participants. These results were validated in 2 independent patient cohorts (Glasgow, n = 198; Germany, n = 468). Aberrant biomarker expression stratified the cohorts into 3 distinct prognostic groups. A preoperative nomogram incorporating S100A2 and S100A4 expression predicted survival and nomograms derived using postoperative clinicopathological variables. CONCLUSIONS: Of those patients with a poor preoperative nomogram score, approximately 50% of patients died within a year of resection. Nomograms have the potential to improve selection for surgery and neoadjuvant therapy, avoiding surgery in aggressive disease, and justifying more extensive resections in biologically favorable disease.

The effect of antibiotics on clinical outcomes in immune-checkpoint blockade: a systematic review and meta-analysis of observational studies.

PURPOSE: Pre-clinical and early clinical data suggests the microbiome plays an important role in oncogenesis and influences response to immune checkpoint blockade (ICB). The objective of this systematic review and meta-analysis was to determine whether antibiotics affect overall survival (OS) and progression free survival (PFS) in patients with solid malignancies treated with ICB. PATIENTS AND METHODS: A systematic search of EMBASE, MEDLINE and conference proceedings was conducted for observational studies examining the effect of antibiotics on ICB. A random effects study-level meta-analysis was performed with pooling of the hazards ratio (HR) for OS and PFS. Meta-regression was used to determine the impact of the timing of antibiotic exposure on OS. RESULTS: 766 studies were identified, and 18 studies met the inclusion criteria. Of the 2889 patients included, 826 (28.6%) were exposed to antibiotics. The most common malignancies were lung (59%), renal cell carcinoma (RCC) or urothelial carcinoma (16.3%) and melanoma (18.7%). OS was prolonged in those without antibiotic exposure (pooled HR 1.92, 95% CI 1.37-2.68, p < 0.001). The effect of antibiotics on OS was greater in studies defining antibiotic exposure as 42 days prior to initiation of ICB (HR 3.43, 95% CI 2.29-5.14, p < 0.0001). PFS was also longer in patients who did not receive antibiotics (pooled HR 1.65, 95% CI 1.3-2.1, p < 0.0001). CONCLUSION: In patients receiving ICB, OS and PFS are longer in patients who are not exposed to antibiotics. Antibiotic use in the 42 days before starting ICB appears to be most detrimental to outcome.

Tailored first-line and second-line CDK4-targeting treatment combinations in mouse models of pancreatic cancer.

OBJECTIVE: Extensive molecular heterogeneity of pancreatic ductal adenocarcinoma (PDA), few effective therapies and high mortality make this disease a prime model for advancing development of tailored therapies. The p16-cyclin D-cyclin-dependent kinase 4/6-retinoblastoma (RB) protein (CDK4) pathway, regulator of cell proliferation, is deregulated in PDA. Our aim was to develop a novel personalised treatment strategy for PDA based on targeting CDK4. DESIGN: Sensitivity to potent CDK4/6 inhibitor PD-0332991 (palbociclib) was correlated to protein and genomic data in 19 primary patient-derived PDA lines to identify biomarkers of response. In vivo efficacy of PD-0332991 and combination therapies was determined in subcutaneous, intrasplenic and orthotopic tumour models derived from genome-sequenced patient specimens and genetically engineered model. Mechanistically, monotherapy and combination therapy were investigated in the context of tumour cell and extracellular matrix (ECM) signalling. Prognostic relevance of companion biomarker, RB protein, was evaluated and validated in independent PDA patient cohorts (>500 specimens). RESULTS: Subtype-specific in vivo efficacy of PD-0332991-based therapy was for the first time observed at multiple stages of PDA progression: primary tumour growth, recurrence (second-line therapy) and metastatic setting and may potentially be guided by a simple biomarker (RB protein). PD-0332991 significantly disrupted surrounding ECM organisation, leading to increased quiescence, apoptosis, improved chemosensitivity, decreased invasion, metastatic spread and PDA progression in vivo. RB protein is prevalent in primary operable and metastatic PDA and may present a promising predictive biomarker to guide this therapeutic approach. CONCLUSION: This study demonstrates the promise of CDK4 inhibition in PDA over standard therapy when applied in a molecular subtype-specific context.

Hypermutation In Pancreatic Cancer.

Pancreatic cancer is molecularly diverse, with few effective therapies. Increased mutation burden and defective DNA repair are associated with response to immune checkpoint inhibitors in several other cancer types. We interrogated 385 pancreatic cancer genomes to define hypermutation and its causes. Mutational signatures inferring defects in DNA repair were enriched in those with the highest mutation burdens. Mismatch repair deficiency was identified in 1% of tumors harboring different mechanisms of somatic inactivation of MLH1 and MSH2. Defining mutation load in individual pancreatic cancers and the optimal assay for patient selection may inform clinical trial design for immunotherapy in pancreatic cancer.

Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes.

Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis.

Metastatic pancreatic ductal adenocarcinoma: diagnosis and treatment with a view to the future.

Metastatic pancreatic ductal adenocarcinoma (mPDAC) is a lethal disease with a poor 5-year survival. Systemic treatments can be used to control symptoms and prolong life. Cytotoxic chemotherapies are commonly administered, with combination treatments, such as fluorouracil, folinic acid, irinotecan and oxaliplatin (FOLFIRINOX) or nab-paclitaxel and gemcitabine showing the largest clinical benefits. Newer genomic classifications of PDAC may provide a rationale for targeted therapies or immunotherapies, although at present these remain largely experimental. This review discusses the evidence behind the currently used regimens, while introducing the potential future of pancreatic cancer care.

Rho-associated kinase signalling and the cancer microenvironment: novel biological implications and therapeutic opportunities.

The Rho/ROCK pathway is involved in numerous pivotal cellular processes that have made it an area of intense study in cancer medicine, however, Rho-associated coiled-coil containing protein kinase (ROCK) inhibitors are yet to make an appearance in the clinical cancer setting. Their performance as an anti-cancer therapy has been varied in pre-clinical studies, however, they have been shown to be effective vasodilators in the treatment of hypertension and post-ischaemic stroke vasospasm. This review addresses the various roles the Rho/ROCK pathway plays in angiogenesis, tumour vascular tone and reciprocal feedback from the tumour microenvironment and explores the potential utility of ROCK inhibitors as effective vascular normalising agents. ROCK inhibitors may potentially enhance the delivery and efficacy of chemotherapy agents and improve the effectiveness of radiotherapy. As such, repurposing of these agents as adjuncts to standard treatments may significantly improve outcomes for patients with cancer. A deeper understanding of the controlled and dynamic regulation of the key components of the Rho pathway may lead to effective use of the Rho/ROCK inhibitors in the clinical management of cancer.

Clinical and pathologic features of familial pancreatic cancer.

BACKGROUND: Inherited predisposition to pancreatic cancer contributes significantly to its incidence and presents an opportunity for the development of early detection strategies. The genetic basis of predisposition remains unexplained in a high proportion of patients with familial PC (FPC). METHODS: Clinicopathologic features were assessed in a cohort of 766 patients who had been diagnosed with pancreatic ductal adenocarcinoma (PC). Patients were classified with FPC if they had ≥1 affected first-degree relatives; otherwise, they were classified with sporadic PC (SPC). RESULTS: The prevalence of FPC in this cohort was 8.9%. In FPC families with an affected parent-child pair, 71% in the subsequent generation were 12.3 years younger at diagnosis. Patients with FPC had more first-degree relatives who had an extrapancreatic malignancy (EPM) (42.6% vs 21.2; P<.0001), particularly melanoma and endometrial cancer, but not a personal history of EPM. Patients with SPC were more likely to be active smokers, have higher cumulative tobacco exposure, and have fewer multifocal precursor lesions, but these were not associated with differences in survival. Long-standing diabetes mellitus (>2 years) was associated with poor survival in both groups. CONCLUSIONS: FPC represents 9% of PC, and the risk of malignancy in kindred does not appear to be confined to the pancreas. Patients with FPC have more precursor lesions and include fewer active smokers, but other clinicopathologic factors and outcome are similar to those in patients with SPC. Furthermore, some FPC kindreds may exhibit anticipation. A better understanding of the clinical features of PC will facilitate efforts to uncover novel susceptibility genes and the development of early detection strategies.

Altered presentation of oropharyngeal cancer, a 6-year review.

BACKGROUND: Human papilloma virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) continues to increase in incidence. Patients are younger, non-smokers and most commonly present with a neck mass often with no other symptoms. This altered presentation compared with non-HPV OPSCC may not be recognized by medical practitioners, leading to delayed diagnosis. METHODS: Patients with histopathological confirmation of OPSCC and known HPV and/or P16 status who presented to our institution between 2012-2017 inclusive were included in the study. Demographic data, tumour characteristics and presenting symptoms were retrospectivxely obtained from both electronic- and paper-based records. Descriptive statistics were used to report demographic data and the two sample t-test and Fisher's exact test were used to compare groups based on HPV status. Time to diagnosis was also reported. RESULTS: A total of 184 patients were included in the study. The majority of patients were male (85.4%) and HPV + (85.3%). The tonsillar complex (53.8%) and tongue base (42.4%) were the most common primary sites. HPV+ patients were less likely to smoke (17.8%) and they commonly presented with a neck mass (39.5% alone or with other symptoms 61.2%). Time to diagnosis in the HPV+ group was longer (15 weeks). CONCLUSION: Our review has highlighted the altered presentation of OPSCC due to the increased incidence of HPV infection. We showed a delayed time to diagnosis in HPV+ OPSCC compared with non-HPV disease. This confirms the importance of focusing our efforts on educating medical practitioners and creating further awareness to facilitate early detection and treatment.

MASTL overexpression promotes chromosome instability and metastasis in breast cancer.

MASTL kinase is essential for correct progression through mitosis, with loss of MASTL causing chromosome segregation errors, mitotic collapse and failure of cytokinesis. However, in cancer MASTL is most commonly amplified and overexpressed. This correlates with increased chromosome instability in breast cancer and poor patient survival in breast, ovarian and lung cancer. Global phosphoproteomic analysis of immortalised breast MCF10A cells engineered to overexpressed MASTL revealed disruption to desmosomes, actin cytoskeleton, PI3K/AKT/mTOR and p38 stress kinase signalling pathways. Notably, these pathways were also disrupted in patient samples that overexpress MASTL. In MCF10A cells, these alterations corresponded with a loss of contact inhibition and partial epithelial-mesenchymal transition, which disrupted migration and allowed cells to proliferate uncontrollably in 3D culture. Furthermore, MASTL overexpression increased aberrant mitotic divisions resulting in increased micronuclei formation. Mathematical modelling indicated that this delay was due to continued inhibition of PP2A-B55, which delayed timely mitotic exit. This corresponded with an increase in DNA damage and delayed transit through interphase. There were no significant alterations to replication kinetics upon MASTL overexpression, however, inhibition of p38 kinase rescued the interphase delay, suggesting the delay was a G2 DNA damage checkpoint response. Importantly, knockdown of MASTL, reduced cell proliferation, prevented invasion and metastasis of MDA-MB-231 breast cancer cells both in vitro and in vivo, indicating the potential of future therapies that target MASTL. Taken together, these results suggest that MASTL overexpression contributes to chromosome instability and metastasis, thereby decreasing breast cancer patient survival.

Effective modulation of stromal signaling through ROCK inhibition: Is it all in the timing?

Our recent publication demonstrates that transient inhibition of Rho-associated kinase signaling within stroma, significantly decreased in vivo primary tumor growth, metastasis and improved response to standard-of-care therapy in pancreatic cancer. Automated analysis of collagen organization in patient tumors may present a promising tool to predict response to our proposed treatment.

Transient tissue priming via ROCK inhibition uncouples pancreatic cancer progression, sensitivity to chemotherapy, and metastasis.

The emerging standard of care for patients with inoperable pancreatic cancer is a combination of cytotoxic drugs gemcitabine and Abraxane, but patient response remains moderate. Pancreatic cancer development and metastasis occur in complex settings, with reciprocal feedback from microenvironmental cues influencing both disease progression and drug response. Little is known about how sequential dual targeting of tumor tissue tension and vasculature before chemotherapy can affect tumor response. We used intravital imaging to assess how transient manipulation of the tumor tissue, or "priming," using the pharmaceutical Rho kinase inhibitor Fasudil affects response to chemotherapy. Intravital Förster resonance energy transfer imaging of a cyclin-dependent kinase 1 biosensor to monitor the efficacy of cytotoxic drugs revealed that priming improves pancreatic cancer response to gemcitabine/Abraxane at both primary and secondary sites. Transient priming also sensitized cells to shear stress and impaired colonization efficiency and fibrotic niche remodeling within the liver, three important features of cancer spread. Last, we demonstrate a graded response to priming in stratified patient-derived tumors, indicating that fine-tuned tissue manipulation before chemotherapy may offer opportunities in both primary and metastatic targeting of pancreatic cancer.

Second-line treatment in inoperable pancreatic adenocarcinoma: A systematic review and synthesis of all clinical trials.

There remains uncertainty regarding the optimal second-line chemotherapy in advanced pancreatic ductal adenocarcinoma (PDAC). The current recommendation of 5-fluorouracil and oxaliplatin may not be relevant in current practice, as FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan and oxaliplatin) has become a more popular first line therapy in fit patients. The majority of studies in this setting are single-arm Phase II trials with significant heterogeneity of patient populations, treatments and outcomes. In this review, we sought to systematically review and synthesise all prospective data available for the second-line treatment of advanced PDAC.

The dynamics of Rho GTPase signaling and implications for targeting cancer and the tumor microenvironment.

Numerous large scale genomics studies have demonstrated that cancer is a molecularly heterogeneous disease, characterized by acquired changes in the structure and DNA sequence of tumor genomes. More recently, the role of the equally complex tumor microenvironment in driving the aggressiveness of this disease is increasingly being realized. Tumor cells are surrounded by activated stroma, creating a dynamic environment that promotes cancer development, metastasis and chemoresistance. The Rho family of small GTPases plays an essential role in the regulation of cell shape, cytokinesis, cell adhesion, and cell motility. Importantly, these processes need to be considered in the context of a complex 3-dimensional (3D) environment, with reciprocal feedback and cross-talk taking place between the tumor cells and host environment. Here we discuss the role of molecular networks involving Rho GTPases in cancer, and the therapeutic implications of inhibiting Rho signaling in both cancer cells and the emerging concept of targeting the surrounding stroma.

Precision Medicine for Advanced Pancreas Cancer: The Individualized Molecular Pancreatic Cancer Therapy (IMPaCT) Trial.

PURPOSE: Personalized medicine strategies using genomic profiling are particularly pertinent for pancreas cancer. The Individualized Molecular Pancreatic Cancer Therapy (IMPaCT) trial was initially designed to exploit results from genome sequencing of pancreatic cancer under the auspices of the International Cancer Genome Consortium (ICGC) in Australia. Sequencing revealed small subsets of patients with aberrations in their tumor genome that could be targeted with currently available therapies. EXPERIMENTAL DESIGN: The pilot stage of the IMPaCT trial assessed the feasibility of acquiring suitable tumor specimens for molecular analysis and returning high-quality actionable genomic data within a clinically acceptable timeframe. We screened for three molecular targets: HER2 amplification; KRAS wild-type; and mutations in DNA damage repair pathways (BRCA1, BRCA2, PALB2, ATM). RESULTS: Tumor biopsy and archived tumor samples were collected from 93 patients and 76 were screened. To date 22 candidate cases have been identified: 14 KRAS wild-type, 5 cases of HER2 amplification, 2 mutations in BRCA2, and 1 ATM mutation. Median time from consent to the return of validated results was 21.5 days. An inability to obtain a biopsy or insufficient tumor content in the available specimen were common reasons for patient exclusion from molecular analysis while deteriorating performance status prohibited a number of patients from proceeding in the study. CONCLUSIONS: Documenting the feasibility of acquiring and screening biospecimens for actionable molecular targets in real time will aid other groups embarking on similar trials. Key elements include the need to better prescreen patients, screen more patients, and offer more attractive clinical trial options.

Role of FDG-PET in surgical management of patients with colorectal liver metastases.

BACKGROUND: [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is reported to change the management in 20-56% of patients with recurrent or metastatic colorectal cancer. It is not clear if FDG-PET has a role in all such patients or only a subgroup. The aim of the present study was to assess the influence of FDG-PET on the surgical management of patients with known or suspected colorectal liver metastases. METHODS: Patients undergoing FDG-PET for investigation of known or suspected colorectal liver metastases were identified from a South Australian database. Case notes were reviewed retrospectively to determine the influence of FDG-PET findings on patient management. Findings from FDG-PET scanning were compared with findings from conventional diagnostic investigations and operative findings. RESULTS: Overall, in four of 16 patients (25%) management was influenced by FDG-PET findings. FDG-PET altered management in four of eight (50%) patients with non-diagnostic liver lesions on computed tomography (CT) or with elevated carcinoembryonic antigen levels but no liver lesion on CT. In all eight patients with CT diagnosed resectable liver metastases, the addition of FDG-PET did not influence the management. CONCLUSIONS: The findings support the use of FDG-PET in the assessment of selected patients with suspected colorectal liver metastases and equivocal findings on conventional diagnostic investigation.

Personalising pancreas cancer treatment: When tissue is the issue.

The treatment of advanced pancreatic cancer has not moved much beyond single agent gemcitabine until recently when protocols such as FOLFIRINOX (fluorouracil, leucovorin, irinotecan and oxaliplatin) and nab-paclitaxel-gemcitabine have demonstrated some improved outcomes. Advances in technology especially in massively parallel genome sequencing has progressed our understanding of the biology of pancreatic cancer especially the candidate signalling pathways that are involved in tumourogenesis and disease course. This has allowed identification of potentially actionable mutations that may be targeted by new biological agents. The heterogeneity of pancreatic cancer makes tumour tissue collection important with the aim of being able to personalise therapies for the individual as opposed to a one size fits all approach to treatment of the condition. This paper reviews the developments in this area of translational research and the ongoing clinical studies that will attempt to move this into the everyday oncology practice.

Histomolecular phenotypes and outcome in adenocarcinoma of the ampulla of vater.

PURPOSE: Individuals with adenocarcinoma of the ampulla of Vater demonstrate a broad range of outcomes, presumably because these cancers may arise from any one of the three epithelia that converge at that location. This variability poses challenges for clinical decision making and the development of novel therapeutic strategies. PATIENTS AND METHODS: We assessed the potential clinical utility of histomolecular phenotypes defined using a combination of histopathology and protein expression (CDX2 and MUC1) in 208 patients from three independent cohorts who underwent surgical resection for adenocarcinoma of the ampulla of Vater. RESULTS: Histologic subtype and CDX2 and MUC1 expression were significant prognostic variables. Patients with a histomolecular pancreaticobiliary phenotype (CDX2 negative, MUC1 positive) segregated into a poor prognostic group in the training (hazard ratio [HR], 3.34; 95% CI, 1.69 to 6.62; P < .001) and both validation cohorts (HR, 5.65; 95% CI, 2.77 to 11.5; P < .001 and HR, 2.78; 95% CI, 1.25 to 7.17; P = .0119) compared with histomolecular nonpancreaticobiliary carcinomas. Further stratification by lymph node (LN) status defined three clinically relevant subgroups: one, patients with histomolecular nonpancreaticobiliary (intestinal) carcinoma without LN metastases who had an excellent prognosis; two, those with histomolecular pancreaticobiliary carcinoma with LN metastases who had a poor outcome; and three, the remainder of patients (nonpancreaticobiliary, LN positive or pancreaticobiliary, LN negative) who had an intermediate outcome. CONCLUSION: Histopathologic and molecular criteria combine to define clinically relevant histomolecular phenotypes of adenocarcinoma of the ampulla of Vater and potentially represent distinct diseases with significant implications for current therapeutic strategies, the ability to interpret past clinical trials, and future trial design.