Inhibition of P21-activated kinases 1 and 4 synergistically suppresses the growth of pancreatic cancer by stimulating anti-tumour immunity.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal types of cancer, and KRAS oncogene occurs in over 90% of cases. P21-activated kinases (PAK), containing six members (PAK1 to 6), function downstream of KRAS. PAK1 and PAK4 play important roles in carcinogenesis, but their combinational effect remains unknown. In this study, we have determined the effect of dual inhibition of PAK1 and PAK4 in PDA progression using knockout (KO) cancer cell lines. METHODS: Murine wild-type (WT) and PAK1KO pancreatic cancer cell lines were isolated from PAK1+/+ and PAK1-/- KPC (LSL-KrasG12D/+; LSL-Trp53 R172H/+; Pdx-1-Cre) mice. KPC PAK4KO and KPC PAK1&4 KO cell lines were generated from KPC WT and KPC PAK1KO cell lines respectively using the CRISPR-CAS9 gene knockout technique. PAK WT and KO cell lines were used in mouse models of pancreatic tumours. Cells and tumour tissue were also used in flow cytometry and proteomic studies. A human PDA tissue microarray was stained by immunohistochemistry. RESULTS: Double knock out of PAK1 and PAK4 caused complete regression of tumour in a syngeneic mouse model. PAK4KO inhibited tumour growth by stimulating a rapid increase of cytotoxic CD8+ T cell infiltration. PAK1KO synergistically with PAK4KO increased cytotoxic CD8+ T cell infiltration and stimulated a sustained infiltration of CD8+ T cells at a later phase to overcome the immune evasion in the PAK4KO tumour. The human PDA tissue microarray study showed the important role of PAK1 and PAK4 in intra-tumoral T-cell function. CONCLUSION: Our results demonstrated that dual inhibition of PAK1 and PAK4 synergistically suppressed PDA progression by stimulating cytotoxic CD8 + T cell response.

Real-world prevalence of PD-L1 expression in non-small cell lung cancer: an Australia-wide multi-centre retrospective observational study.

An investigator-initiated, Australia-wide multi-centre retrospective observational study was undertaken to investigate the real-world prevalence of programmed death ligand-1 (PD-L1) expression in non-small cell lung carcinoma (NSCLC). Multiple centres around Australia performing PD-L1 immunohistochemistry (IHC) were invited to participate. Histologically confirmed NSCLC of any stage with a PD-L1 IHC test performed for persons aged ≥18 years between 1 January 2018 and 1 January 2020, and eligible for review, were identified at each centre, followed by data extraction and de-identification, after which data were submitted to a central site for collation and analysis. In total data from 6690 eligible PD-L1 IHC tests from histologically (75%) or cytologically (24%) confirmed NSCLC of any stage were reviewed from persons with a median age of 70 years, 43% of which were female. The majority (81%) of tests were performed using the PD-L1 IHC SP263 antibody with the Ventana BenchMark Ultra platform and 19% were performed using Dako PD-L1 IHC 22C3 pharmDx assay. Reported PD-L1 tumour proportion score (TPS) was ≥50% for 30% of all tests, with 62% and 38% scoring PD-L1 ≥1% and <1%, respectively. Relative prevalence of clinicopathological features with PD-L1 scores dichotomised to <50% and ≥50%, or to <1% and ≥1%, were examined. Females scored ≥1% slightly more often than males (64% vs 61%, respectively, p=0.013). However, there was no difference between sexes or age groups (<70 or ≥70 years) where PD-L1 scored ≥50%. Specimens from patients with higher stage (III/IV) scored ≥1% or ≥50% marginally more often compared to specimens from patients with lower stage (I/II) (p≤0.002). Proportions of primary and metastatic specimens did not differ where PD-L1 TPS was ≥1%, however more metastatic samples scored TPS ≥50% than primary samples (metastatic vs primary; 34% vs 27%, p<0.001). Cytology and biopsy specimens were equally reported, at 63% of specimens, to score TPS ≥1%, whereas cytology samples scored TPS ≥50% slightly more often than biopsy samples (34% vs 30%, respectively, p=0.004). Resection specimens (16% of samples tested) were reported to score TPS ≥50% or ≥1% less often than either biopsy or cytology samples (p<0.001). There was no difference in the proportion of tests with TPS ≥1% between PD-L1 IHC assays used, however the proportion of tests scored at TPS ≥50% was marginally higher for 22C3 compared to SP263 (34% vs 29%, respectively, p<0.001). These real-world Australian data are comparable to some previously published global real-world data, with some differences noted.

Real-world challenges in undertaking NTRK fusion testing in non-small cell lung cancer.

Background: We performed a retrospective analysis to determine the incidence of neurotrophic tropomyosin-receptor kinase (NTRK) fusion in non-small cell lung cancer (NSCLC). Methods: Archival NSCLC tissues between 2018-2020 were screened by immunohistochemistry (IHC) with IHC-positive cases undergoing confirmatory molecular analysis. Correlative clinicopathologic parameters were collected. Results: Of 289 samples analyzed, 10 (3.5%) cases had NTRK expression on IHC. The median age of patients with NTRK-positivity on IHC was 74.9 (range, 44-88) years and 70% had a smoking history. The cohort included seven adenocarcinomas and one each squamous cell carcinoma, large-cell neuroendocrine and not otherwise specified histologies. PDL1 expression was ≤50% in five cases. Concurrent EGFR mutations were detected in three cases, with two cases also showing a PIK3CA E542K mutation and MET amplification, respectively. Due to insufficient tumor material, RNA-sequencing was undertaken in only one IHC-positive case, with the other nine cases analyzed by Fluorescent in-situ Hybridisation. A NTRK fusion, EML4-NTRK3 gene fusion was detected in one patient, a frequency of 0.35%. Conclusions: NTRK fusions in NSCLC are rare. This study highlights real world diagnostic challenges regarding NTRK testing, such as requirements of adequate tumor tissue and appropriate testing methodologies.

Kikuchi's Disease Diagnosed by an Excisional Biopsy in a Patient With COVID-19.

COVID-19 is an ongoing pandemic caused by the novel coronavirus SARS-CoV-2. The clinical features of COVID-19 are myriad. Though it is a multisystem illness, it predominantly involves the respiratory system. There have been case reports on rare manifestations of COVID-19, of which COVID-19-related Kikuchi's disease is one of them. To our knowledge, this is the third reported case in the world. We report a lady in her late 60s with COVID-19 infection and secondary bacterial pneumonia, which necessitated ICU admission, having ongoing fever spikes with high inflammatory markers and leukopenia. She was also found to have tender cervical lymphadenopathy on the third week of illness, whose biopsy revealed histiocytic necrotizing lymphadenitis in keeping with Kikuchi's disease. The patient had an uneventful recovery in two weeks without any intervention. The pathophysiology of COVID-19-related Kikuchi's disease is unclear. However, COVID-19 is a viral illness that involves changes in interleukins. The latter is postulated in Kikuchi's disease.

Herb-Induced Liver Injury: A Report on Two Australian Cases.

Two 40-year-old males were admitted to our tertiary hepatology unit with acute hepatitis after presentation with generalized abdominal pain, nausea, and jaundice. There was no history of paracetamol overdose, and common viral and autoimmune causes were excluded through serology. Imaging and liver biopsy were performed with both investigations demonstrating non-specific features of hepatic inflammation. A history of herbal supplement use was elucidated in each patient, which was deemed to be the cause of liver injury in both men. Each patient recovered within two months of presentation following the withdrawal of the offending agent and supportive care.

Angiotensin Converting Enzyme-2 Therapy Improves Liver Fibrosis and Glycemic Control in Diabetic Mice With Fatty Liver.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and is frequently associated with type 2 diabetes. However, there is no specific medical therapy to treat this condition. Angiotensin-converting enzyme 2 (ACE2) of the protective renin angiotensin system generates the antifibrotic peptide angiotensin-(1-7) from profibrotic angiotensin II peptide. In this study, we investigated the therapeutic potential of ACE2 in diabetic NAFLD mice fed a high-fat (20%), high-cholesterol (2%) diet for 40 weeks. Mice were given a single intraperitoneal injection of ACE2 using an adeno-associated viral vector at 30 weeks of high-fat, high-cholesterol diet (15 weeks after induction of diabetes) and sacrificed 10 weeks later. ACE2 significantly reduced liver injury and fibrosis in diabetic NAFLD mice compared with the control vector injected mice. This was accompanied by reductions in proinflammatory cytokine expressions, hepatic stellate cell activation, and collagen 1 expression. Moreover, ACE2 therapy significantly increased islet numbers, leading to an increased insulin protein content in ß-cells and plasma insulin levels with subsequent reduction in plasma glucose levels compared with controls. Conclusion: We conclude that ACE2 gene therapy reduces liver fibrosis and hyperglycemia in diabetic NAFLD mice and has potential as a therapy for patients with NAFLD with diabetes.

Case of nivolumab-induced sclerosing cholangitis: lessons from long-term follow-up.

Nivolumab is an immune checkpoint inhibitor used to treat multiple solid-organ malignancies. While many of its immune-related adverse events are well established, nivolumab-induced sclerosing cholangitis remains poorly characterised, with no defined diagnostic criteria. Moreover, data regarding long-term outcomes are particularly lacking. We present a biopsy-proven case of nivolumab-induced sclerosing cholangitis, which uniquely captures 18 months of follow-up post-treatment. Our case highlights key features of intrahepatic subtype sclerosing cholangitis and suggests durable response to corticosteroid therapy.

NTRK and ALK rearrangements in malignant pleural mesothelioma, pulmonary neuroendocrine tumours and non-small cell lung cancer.

OBJECTIVES: Gene rearrangements involving NTRK1, NTRK2, NTRK3, ROS1 and ALK have been identified in many types of cancer, including non-small cell lung cancer (NSCLC). Data in malignant pleural mesothelioma (MPM), lung neuroendocrine tumors (NETs) and small-cell lung cancer (SCLC) are lacking. Given the activity of NTRK, ROS-1 and ALK inhibitors in tumors harboring gene fusions, we sought to explore such rearrangements in these less common tumors in addition to NSCLC. METHODS: Archival tumor tissue from patients with MPM, lung NETs, SCLC and NSCLC were used to create tissue microarrays. Immunohistochemistry (IHC) was performed using a cocktail of antibodies against TRK, ROS1 and ALK. IHC positive samples underwent RNA sequencing using the ArcherDX FusionPlex CTL diagnostic assay. Clinical data were obtained through retrospective chart review. RESULTS: We performed IHC on 1116 samples: 335 MPMs, 522 NSCLCs, 105 SCLCs and 154 lung NETs. There were 23 IHC positive cases (2.1%) including eight MPMs (2.4%), eight NETs (5.2%), five SCLC (4.8%) and two NSCLC (0.4%). The following fusions were detected: one MPM with an NTRK ex10-TPM3 ex8, another MPM with an ALK ex20-EML4ex13, one lung intermediate-grade NET (atypical carcinoid) with an ALK ex20-EML4 ex6/intron6, and two NSCLCs with an ALK ex20-EML4 ex6/intron6 rearrangement. None of the patients received targeted treatment. CONCLUSIONS: To our knowledge, we report for the first time NTRK and ALK rearrangements in a small subset of MPM. An ALK rearrangement was also detected in lung intermediate-grade NET (or atypical carcinoid). Our data suggest that IHC could be a useful screening test in such patients to ensure that all therapeutic strategies including targeted therapy are utilized.

Hepatitis B virus activity is not associated with degree of liver steatosis in patients with hepatitis B-related chronic liver disease.

BACKGROUND & AIMS: The recently published manuscript by Zhu and colleagues "Hepatitis B virus infection and risk of non-alcoholic fatty liver disease: A population-based cohort study" found no correlation between presence of chronic HBV and presence of common risk factors for non-alcoholic fatty liver disease on primary analysis. A limitation to this study, like most population based research, is the absence of liver histology, which is considered gold standard for assessment of non-alcoholic fatty liver disease. METHODS: Our group studied the association between hepatitis B viral activity and non-alcoholic fatty liver disease activity as measured by grade of steatohepatitis/fibrosis on liver biopsy by analysing consecutive liver histology samples from patients with chronic hepatitis B at a single quaternary liver transplant centre. RESULTS: Linear regression modelling for active viral hepatitis on histological examination against degree of steatohepatitis showed no correlation (r2  = .018, all P> .1). Linear regression of degree of steatohepatitis vs hepatitis B viral load also showed no correlation. CONCLUSIONS: Our work is concordant with the manuscript from Zhu et al; we found no significant correlation between hepatitis B viral activity and degree of steatohepatitis.

Liver-Targeted Angiotensin Converting Enzyme 2 Therapy Inhibits Chronic Biliary Fibrosis in Multiple Drug-Resistant Gene 2-Knockout Mice.

There is a large unmet need for effective therapies for cholestatic disorders, including primary sclerosing cholangitis (PSC), a disease that commonly results in liver failure. Angiotensin (Ang) II of the renin Ang system (RAS) is a potent profibrotic peptide, and Ang converting enzyme 2 (ACE2) of the alternate RAS breaks down Ang II to antifibrotic peptide Ang-(1-7). In the present study, we investigated long-term effects of ACE2 delivered by an adeno-associated viral vector and short-term effects of Ang-(1-7) peptide in multiple drug-resistant gene 2-knockout (Mdr2-KO) mice. These mice develop progressive biliary fibrosis with pathologic features closely resembling those observed in PSC. A single intraperitoneal injection of ACE2 therapy markedly reduced liver injury (P < 0.05) and biliary fibrosis (P < 0.01) at both established (3-6 months of age) and advanced (7-9 months of age) disease compared to control vector-injected Mdr2-KO mice. This was accompanied by increased hepatic Ang-(1-7) levels (P < 0.05) with concomitant reduction in hepatic Ang II levels (P < 0.05) compared to controls. Moreover, Ang-(1-7) peptide infusion improved liver injury (P < 0.05) and biliary fibrosis (P < 0.0001) compared to saline-infused disease controls. The therapeutic effects of both ACE2 therapy and Ang-(1-7) infusion were associated with significant (P < 0.01) reduction in hepatic stellate cell (HSC) activation and collagen expression. While ACE2 therapy prevented the loss of epithelial characteristics of hepatocytes and/or cholangiocytes in vivo, Ang-(1-7) prevented transdifferentiation of human cholangiocytes (H69 cells) into the collagen-secreting myofibroblastic phenotype in vitro. We showed that an increased ratio of hepatic Ang-(1-7) to Ang II levels by ACE2 therapy results in the inhibition of HSC activation and biliary fibrosis. Conclusion: ACE2 therapy has the potential to treat patients with biliary diseases, such as PSC.

Hepatic angiosarcoma as a cause of acute liver failure.

Hepatic angiosarcoma is an extremely rare disease entity that accounts for approximately 0.1%-2% of primary liver malignancy. It is three times more common in men than women and usually affects the former in their sixth or seventh decade of life. Risk factors for the development of hepatic angiosarcoma include the use of oral contraceptives, exposure to anabolic steroids, radiation, thorium dioxide, arsenic and vinyl chloride. The prognosis of hepatic angiosarcoma is extremely poor which is attributable to early metastases to other organs, resistance to traditional chemotherapy and radiotherapy regimens and rapid progression of the tumour. Optimal management of patients is poorly demarcated due to the rarity of the tumour. We present a case series of two patients: one who passed away due to acute hepatic failure secondary to hepatic angiosarcoma and the second who underwent a liver transplantation and was subsequently diagnosed with hepatic angiosarcoma based on his explant histology.

Mycophenolate mofetil toxicity mimicking acute cellular rejection in a small intestinal transplant.

Mycophenolate mofetil (MMF) is an important medication used for maintenance immunosuppression in solid organ transplants. A common gastrointestinal (GI) side effect of MMF is enterocolitis, which has been associated with multiple histological features. There is little data in the literature describing the histological effects of MMF in small intestinal transplant (SIT) recipients. We present a case of MMF toxicity in a SIT recipient, with histological changes in the donor ileum mimicking persistent acute cellular rejection (ACR). Concurrent biopsies of the patient's native colon showed similar changes to those from the donor small bowel, suggesting a non-graft specific process, raising suspicion for MMF toxicity. The MMF was discontinued and complete resolution of these changes occurred over three weeks. MMF toxicity should therefore be considered as a differential diagnosis for ACR and graft-versus-host disease in SITs.

Gastric adenocarinoma of the upper oesophagus: A literature review and case report.

BACKGROUND: Ectopic gastric mucosa (EGM) otherwise termed gastric heterotopia or gastric inlet patch occurs in approximately 2.5% of the population. Adenocarcinoma uncommonly involves the upper oesophagus, rarely arising from gastric heterotopia or submucosal glands. Currently, there are 58 cases in the literature of oesophageal adenocarcinoma arising within areas of EGM. To date no paper has differentiated between gastric or intestinal type adenocarcinoma. This case, which describes adenocarcinoma arising within EGM, exhibited a different immunophenotype reminiscent of gastric type glands, in the absence of intestinal metaplasia. This case should be regarded as a different type of carcinoma, consistent with a non-Barrett's oesophagus-associated adenocarcinoma. CLINICAL PRESENTATION: A 63year old female presented with a three month history of progressive cervical dysphagia with no associated weight loss or general malaise. Gastroscopy revealed a suspicious lesion at the cricopharyngeus. Positron emission tomography demonstrated a metabolically active primary lesion without evidence of distant disease. The patient received neo-adjuvant chemotherapy followed by a three stage total oesophagectomy. Histology demonstrated a moderately differentiated adenocarcinoma with gastric immunophenotype and background changes of gastric heterotopia. CONCLUSION: EGM is common but scarcely biopsied for evidence of dysplasia or adenocarcinoma. Whilst malignant progression is rare it is important that endoscopists are aware of the potential. Determining the exact type of adenocarcinoma may have implications for therapeutic approaches. Recognition of EGM at endoscopy may identify patients at greater risk of developing adenocarcinomas of the proximal oesophagus, however, this relationship and the necessity for screening requires more study.

Calretinin but not caveolin-1 correlates with tumour histology and survival in malignant mesothelioma.

Malignant mesothelioma (MM) continues to be a disease with poor prognosis and limited treatment options. Calretinin and caveolin-1 expression by tumour in MM have recently been described to be associated with tumour histology, differentiation and consequently survival. In a large, well annotated cohort, we studied both of these biomarkers and explored their association with clinicopathological parameters and survival. A retrospective search of patients with MM who underwent surgery at the Austin Hospital in Melbourne, Australia, was conducted. Clinical history and outcome data were retrieved from patient records. Tissue microarrays (TMAs) were constructed and stained for calretinin and caveolin-1. 'H scores' were derived, taking intensity and distribution of staining, and the cohort was dichotomised using median values for both markers. In the 329 patients evaluated, median age was 67 years. Males outnumbered females by 5:1. Epithelioid histology 202/319 (62.9%) was the most common, followed by biphasic 72/319 (21.8%) and sarcomatoid 45/319 (13.6%); histology could not be confirmed in 10 patients. Calretinin expression was detected in 246 of the 324 (76%) evaluable patients and high expression was associated with epithelioid histology (p < 0.0001). Caveolin-1 was expressed in 298 (94%) of 317 evaluable patients which was much higher compared to its expression in a cohort of lung adenocarcinomas (8/58, 13.7%). However, no association with histology was found (p = 0.409). When taken as a continuous variable, calretinin expression was found to be an independent predictor of survival, alongside histology, neutrophil-lymphocyte ratio, weight loss and stage. No prognostic value was demonstrable for caveolin-1 expression and calretinin/caveolin-1 ratio. There was no relationship between calretinin and caveolin-1 expression. In MM, increased calretinin expression is associated with epithelioid histology and better survival. Caveolin-1 is a sensitive MM marker and is expressed in a high proportion of cases but lacks association with histology and survival.