Early onset pancreatic cancer-exploring contemporary treatment and outcomes using real-world data

BACKGROUND

Pancreatic cancer incidence is increasing in younger populations. Differences between early onset pancreatic cancer (EOPC) and later onset pancreatic cancer (LOPC), and how these should inform management warrant exploration in the contemporary setting.

METHODS

A prospectively collected multi-site dataset on consecutive pancreatic adenocarcinoma patients was interrogated. Patient, tumour, treatment, and outcome data were extracted for EOPC (≤50 years old) vs LOPC (>50 years old).

RESULTS

Of 1683 patients diagnosed between 2016 and 2022, 112 (6.7%) were EOPC. EOPC more frequently had the tail of pancreas tumours, earlier stage disease, surgical resection, and trended towards increased receipt of chemotherapy in the curative setting compared to LOPC. EOPC more frequently received 1st line chemotherapy, 2nd line chemotherapy, and chemoradiotherapy than LOPC in the palliative setting. Recurrence-free survival was improved for the tail of pancreas EOPC vs LOPC in the resected setting; overall survival was superior for EOPC compared to LOPC across the resected, locally advanced unresectable and metastatic settings.

CONCLUSIONS

EOPC remains a small proportion of pancreatic cancer diagnoses. The more favourable outcomes in EOPC suggest these younger patients are overall deriving benefits from increased treatment in the curative setting and increased therapy in the palliative setting.

Immune checkpoint inhibitor therapy for advanced cutaneous squamous cell carcinoma in Australia: a retrospective real world cohort study

OBJECTIVES

To review the outcomes of immune checkpoint inhibitor (ICI) treatment of advanced cutaneous squamous cell carcinoma (CSCC) outside clinical trials.

STUDY DESIGN

Retrospective observational study; review of patient records in fifteen Australian institutions.

SETTING, PARTICIPANTS

All Australian adults with locally advanced or metastatic CSCC not amenable to curative surgery or radiotherapy treated with ICIs, 5 May 2017 - 23 May 2022, through a cemiplimab compassionate access scheme (Therapeutic Goods Administration Special Access Scheme) or who personally covered the cost of pembrolizumab prior to the start of the access scheme.

MAIN OUTCOME MEASURES

Best overall response rate (ORR) according to standardised assessment criteria using the hierarchy: Response Evaluation Criteria in Solid Tumors (RECIST 1.1), the modified World Health Organization clinical response criteria, and the Positron Emission Tomography Response Criteria (PERCIST 1.0); overall and progression-free survival.

RESULTS

A total of 286 people with advanced CSCC received ICI therapy during May 2017 - May 2022 (cemiplimab, 270; pembrolizumab, 16). Their median age was 75.2 years (range, 39.3-97.5 years) and 232 were men (81%); median follow-up time was 12.2 months (interquartile range, 5.5-20.5 months). Eighty-eight people (31%) were immunocompromised, 27 had autoimmune disease, and 59 of 277 (21%) had ECOG performance scores of 2 or 3. The ORR was 60% (166 of 278 evaluable patients): complete responses were recorded for 74 (27%) and partial responses for 92 patients (33%). Twelve-month overall survival was 78% (95% confidence interval [CI], 72-83%); progression-free survival was 65% (95% CI, 58-70%). Poorer ECOG performance status was associated with poorer overall survival (per unit: adjusted hazard ratio [aHR], 3.0; 95% CI, 2.0-4.3) and progression-free survival (aHR, 2.4; 95% CI, 1.8-3.3), as was being immunocompromised (overall: aHR, 1.8; 95% CI, 1.1-3.0; progression-free: aHR, 1.8; 95% CI, 1.2-2.7). Fifty-five people (19%) reported immune-related adverse events of grade 2 or higher; there were no treatment-related deaths.

CONCLUSION

In our retrospective study, the effectiveness and toxicity of ICI therapy were similar to those determined in clinical trials. Our findings suggest that ICIs could be effective and well tolerated by people with advanced CSCC who are ineligible for clinical trials.

Rice Bran Arabinoxylan Compound and Quality of Life (RBAC-QoL) of Cancer Patients: An Interim Analysis of the RBAC-QoL Study

Background The effect of rice bran arabinoxylan compound (RBAC), a plant-based immunomodulator, on the quality of life (QoL) in cancer patients and underlying physiological pathways remains unclear. Trial design The RBAC-QoL study, a double-blind, randomised, controlled pilot feasibility study, aimed to determine RBAC's effects on QoL and the associated action mechanisms. Primary outcomes were the EORTC QLQ-C30 functional, symptom, and global QoL scores with inflammatory, nutritional, and cytokine parameters as secondary and exploratory outcomes. Methods Participants were adults diagnosed with solid organ tumours (≥ stage II) undergoing active treatment in several outpatient centres in New South Wales, Australia. Interventions were RBAC or matched placebo at 3g/day for 24 weeks allocated through stratified randomisation with participants, oncologists, and data collectors blinded. Data was collected from five study visits six weeks apart. The trial remained ongoing as of December 2023. An interim intention-to-treat analysis was performed using repeated measure ANOVA with pairwise comparisons where statistical significance was observed and adjusted with covariates. Results Global QoL scores from currently available data (n = 16; RBAC = 7, placebo = 9) were statistically different between groups (F1,8 = 8.6, p = 0.019, eta2[g] = 0.267). Pairwise comparisons found significant differences at Week 6 (p = 0.032, Cohen's d = 1.454) and marginally at Week 12 (p = 0.069, d = 1.427). Age-adjusted analysis showed a continuous upward trend in QoL improvement over time with RBAC, while the placebo group did not deviate from baseline QoL. Significant elevations of serum white blood cell count (Week 18) and total protein (Weeks 12 and 18) were detected in the RBAC group compared to placebo. The total protein levels correlated highly with white blood cell count (Pearson's r = 0.539, p < 0.001) and moderately with the global QoL scores (r = 0.338, p = 0.01). No intervention-related adverse events were reported in both groups.  Conclusions RBAC improves QoL beyond placebo during active cancer treatment, possibly through the immuno-nutritional pathway - these findings, though preliminary, are valuable for future research. Funding and registration: Daiwa Pharmaceutical Co., Ltd, Japan; BioMedica Nutraceuticals Pty Ltd., Australia. ANZCTR Reg No: ACTRN12619000562178p.

Feasibility and preliminary effectiveness of virtual reality as a patient education tool for people with cancer undergoing immunotherapy: a protocol for a randomised controlled pilot study in a regional setting

INTRODUCTION

Patient education is a critical component of healthcare delivery. However, medical information and knowledge are complex and can be difficult for patients and families to comprehend when delivered verbally. The use of virtual reality (VR) to convey medical information to patients may bridge this communication gap and lead to more effective patient education. It may be of increased value to those with low health literacy and levels of patient activation, in rural and regional settings. The objective of this randomised, single-centre pilot study is to examine the feasibility and preliminary effectiveness of VR as an education tool for people with cancer. The results will provide data to inform the feasibility of a future randomised controlled trial, including sample size calculations.

METHODS AND ANALYSIS

Patients with cancer undergoing immunotherapy will be recruited. A total of 36 patients will be recruited and randomised to one of three trial arms. Participants will be randomised 1:1:1 to receive VR, a two-dimensional video or standard care (ie, verbal communication and information leaflets). Feasibility will be assessed by recruitment rate, practicality, acceptability, usability and related adverse events. The potential impact of VR on patient-reported outcomes (ie, perceived information provision quality, knowledge about immunotherapy and patient activation) will be assessed and stratified by information coping style (ie, monitors vs blunters) whenever statistical analyses are significant. The patient-reported outcomes will be measured at baseline, post-intervention and 2 weeks post-intervention. In addition, semistructured interviews will be conducted with health professionals and participants randomised to the VR trial arm, to further explore acceptability and feasibility.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Greater Western Human Research Ethics Committee, New South Wales Local Health District (2022/ETH01760). Informed consent will be obtained from all participants. Findings will be disseminated via relevant conference presentations and publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ACTRN12622001473752.

'The best thing since sliced bread': Patient experiences of teleoncology in western NSW

OBJECTIVE

This study explored experiences of rural cancer patients who were receiving treatments by remote video-assisted chemotherapy (RVAC) or participating in clinical trials remotely.

SETTING

Participants lived in Coonabarabran or Dubbo in western NSW.

PARTICIPANTS

Seven cancer patients undergoing treatment for breast, bladder or colon cancer, renal cell carcinoma or lymphoma.

DESIGN

Appreciative inquiry informed this qualitative study. Semi-structured interviews were conducted between July 2018 and January 2019 and thematically analysed.

RESULTS

The patient experience of teleoncology was overwhelmingly positive. Patients explained the value of relationships that developed with the local and virtual care team. Patients felt they received better care if they saw the same oncologist for the duration of their treatment and felt RVAC had accommodated this. Teleoncology allowed patients to remain independent because they were able to maintain their usual support mechanisms including family, friends and health care team. Patients described the reduced physical and emotional travel burden in addition to reduction in travel time and cost.

CONCLUSIONS

These findings highlight the acceptability of teleoncology for rural patients as chemotherapy can be added to the health care and social and emotional supports, which exist in their hometown. Expansion of teleoncology should be codesigned with local communities with a focus on establishing care teams with consistent staffing to build trust between the treating team and the patient. These relationships improve the patient experience and enhance patient independence, which is a desirable attribute of cancer survivorship. Recruitment to clinical trials using teleoncology is acceptable and should be factored into trial development.

Use and outcomes from neoadjuvant chemotherapy in borderline resectable pancreatic ductal adenocarcinoma in an Australasian population

BACKGROUND

Use of neoadjuvant (NA) chemotherapy is recommended when pancreatic ductal adenocarcinoma (PDAC) is borderline resectable METHOD: A retrospective analysis of consecutive patients with localized PDAC between January 2016 and March 2019 within the Australasian Pancreatic Cancer Registry (PURPLE, Pancreatic cancer: Understanding Routine Practice and Lifting End results) was performed. Clinicopathological characteristics, treatment, and outcome were analyzed. Overall survival (OS) comparison was performed using log-rank model and Kaplan-Meier analysis.

RESULTS

The PURPLE database included 754 cases with localised PDAC, including 148 (20%) cases with borderline resectable pancreatic cancer (BRPC). Of the 148 BRPC patients, 44 (30%) underwent immediate surgery, 80 (54%) received NA chemotherapy, and 24 (16%) were inoperable. The median age of NA therapy patients was 63 years and FOLFIRINOX (53%) was more often used as NA therapy than gemcitabine/nab-paclitaxel (31%). Patients who received FOLFIRINOX were younger than those who received gemcitabine/nab-paclitaxel (60 years vs. 67 years, p = .01). Surgery was performed in 54% (43 of 80) of BRPC patients receiving NA chemotherapy, with 53% (16 of 30) achieving R0 resections. BRPC patients undergoing surgery had a median OS of 30 months, and 38% (9 of 24) achieved R0 resection. NA chemotherapy patients had a median OS of 20 months, improving to 24 months versus 10 months for patients receiving FOLFIRINOX compared to gemcitabine/nab-paclitaxel (Hazard Ratio (HR) .3, p < .0001).

CONCLUSIONS

NA chemotherapy use in BRPC is increasing in Australia. One half of patients receiving NA chemotherapy proceed to curative resection, with 53% achieving R0 resections. Patients receiving Infusional 5-flurouracil, Irinotecan and Oxaliplatin (FOLIRINOX) had increased survival than gemcitabine/nab-paclitaxel. Treatment strategies are being explored in the MASTERPLAN and DYNAMIC-Pancreas trials.

Impact of first-line FOLFIRINOX versus Gemcitabine/Nab-Paclitaxel chemotherapy on survival in advanced pancreatic cancer: Evidence from the prospective international multicentre PURPLE pancreatic cancer registry

BACKGROUND

First-line palliative chemotherapy regimens in advanced pancreatic ductal adenocarcinoma (PDAC) have not been compared in head-to-head phase III randomised controlled trials (RCT). Data on optimum first-line treatment and subsequent sequencing is lacking.

OBJECTIVE

To compare overall survival (OS) between first-line treatment regimens in a real-world population to determine if an optimal therapeutic sequence is associated with survival benefit.

METHODS

A retrospective analysis of prospectively collated data from the Australasian PURPLE pancreatic cancer registry was undertaken.

FINDINGS

From 2016 to 2020, of 1551 pancreatic cancer patients, 615 received palliative-intent chemotherapy. Patients with early-stage resected disease without recurrence (n = 369), radiotherapy alone (n = 43), received supportive care alone (n = 458) or had less than 3 months follow-up (n = 66) were excluded. Median OS was comparable between patients receiving first-line Gemcitabine/Nab-Paclitaxel (n = 376) and those receiving FOLFIRINOX (n = 73) (11.3 versus 12.3 months, P = 0.37), with 38% proceeding to second-line chemotherapy which was associated with longer mOS compared to first-line treatment alone (17.4 versus 8.2 months, P &lt; 0.001). With second-line treatment following prior FOLFIRINOX (n = 29) or Gemcitabine/Nab-Paclitaxel (n = 101), mOS did not differ significantly (17.3 versus 15.9 months, P = 0.92), respectively, whilst median progression-free survival was longer with prior FOLFIRINOX (5.2 versus 2.9 months, P = 0.03).

CONCLUSION

There was no significant difference in overall survival between either first-line chemotherapy choice, despite patients receiving FOLFIRINOX being younger, fitter, and more likely to have localised disease. However, FOLFIRINOX was associated with delayed progression. In the absence of phase III RCT data, clinicians should be comfortable using either Gemcitabine/Nab-Paclitaxel or FOLFIRINOX as first-line therapy in advanced PDAC.

Using three scenarios to explain life expectancy in advanced cancer: attitudes of patients, family members, and other healthcare professionals

AIM

To evaluate a web-based tool for estimating and explaining three scenarios for expected survival time to people with advanced cancer (patients), their family members (FMs), and other healthcare professionals (HCPs).

METHODS

Thirty-three oncologists estimated the "median survival of a group of similar patients" for patients seeking quantitative prognostic information. The web-based tool generated worst-case, most likely, and best-case scenarios for survival based on the oncologist's estimate. Oncologists presented the scenarios to each patient and provided a printed summary to patients, FMs, and HCPs. Attitudes to the information were assessed by questionnaires. Observed survival for each patient was compared with the oncologist's estimated survival and the three scenarios.

RESULTS

Prognosis was discussed with 222 patients: median age 67 years; 61% male; most common primary sites pancreas 15%, non-small-cell lung 15%, and colorectal 12%. The median (range) for observed survival times was 9 months (0.5-43) and for oncologist's estimated survival times was 12 months (2-96). Ninety-one percent of patients, 91% of FMs, and 84% of HCPs agreed that it was helpful having life expectancy explained as three scenarios. The majority (77%) of patients judged the information presented about their life expectancy to be the same or better than they had expected before the consultation. The survival estimates met a priori criteria for calibration, precision, and accuracy.

CONCLUSIONS

Patients, FMs, and HCPs found it helpful to receive personalized prognostic information formatted as three scenarios for survival. It was feasible, acceptable, and safe to use a web-based resource to do this.

Virtual reality as a patient education tool in healthcare: A scoping review

OBJECTIVE

To explore what is currently known about the use of virtual reality (VR) as a patient education tool in healthcare.

METHODS

Arksey and O'Malley's scoping review method and the PRISMA-ScR Checklist were employed. Four peer-reviewed databases were searched (Medline, Embase, PsychINFO, the Cochrane library). Pre-defined selection criteria identified 18 studies for inclusion. Results were synthesized using a narrative approach.

RESULTS

VR as an educational tool in healthcare is feasible and acceptable, and may improve patient's knowledge about their illness and satisfaction with treatment. Most studies used the Oculus VR glasses or headset, educated patients though the use of 3D 360° VR anatomical models, and were conducted with people affected with cancer. Opportunities exist for exploring unintended consequences, and the role of VR in educating populations with lower health literacy.

CONCLUSION

VR could assist in communicating medical information and knowledge to patients, but more research is needed, particularly to identify for whom and in what situations this method is most useful and to improve understanding about the potential unintended consequences.

PRACTICE IMPLICATIONS

Health professionals should consider using VR to educate their patients, and researchers can use this as a road map on how to address knowledge gaps in this field.

Early-onset pancreatic cancer: Defining contemporary presentation, treatment, and outcomes in the under 50 age group using real-world data

533

Background: The incidence of pancreatic cancer is increasing in younger patients (pts). Early onset pancreatic cancer (EOPC) is reportedly diagnosed at a later stage, potentially compromising outcomes compared to later onset pts (LOPC). With recent gains in staging and neo/adjuvant regimens, we sought to elaborate on the characteristics of EOPC and LOPC in a contemporary real-world cohort. Methods: The PURPLE registry, a prospectively collected multi-site data set on consecutive pancreatic cancer pts was interrogated. Patient, tumor, treatment and outcome data were extracted for EOPC vs LOPC. EOPC were those diagnosed prior to age 50 and LOPC after age 50. Resectability status was per MDT consensus. Results: Of 1534 pts, 93 (6%) were EOPC (51% male) and 1442 (94%) LOPC (51% male). EOPC had better ECOG performance status (0-1: 95% vs 81%, Relative Risk [RR] 1.2, p < 0.001) and Charlson Comorbidity Index Score (0-2: 98% vs 28%, RR 3.5, p < 0.001). Primary tumor site (head/body/tail: 66%/11%/20% for EOPC and 68%/17%/14% for LOPC), and staging (resectable/borderline resectable/locally advanced/metastatic: 29%/16%/14%/41% for EOPC vs 28%/9%/21%/41% for LOPC) did not differ. 25 (93%) of EOPC and 320 (79%) LOPC resectable pts underwent resection (p = 0.13). 12 (80%) EOPC and 36 (26%) LOPC borderline resectable pts underwent resection (RR 3.0, p < 0.001). Resection margin status (R0 vs R1 vs R2) did not differ. Resected EOPC more frequently received neoadjuvant therapy (30% vs 9%, RR 3.2, p = 0.001). EOPC were more likely to receive palliative chemotherapy in the advanced/metastatic setting (77% vs 49%, RR 1.6, p < 0.001), and were more likely to receive first line (1L) FOLFIRINOX than gemcitabine-nab-paclitaxel (36% vs 18%, RR 2, p = 0.019). Median overall survival (OS) was superior for EOPC (24 vs 12 months, Hazard Ratio [HR] 0.55, p < 0.001). For resectable pts, relapse free survival (RFS) did not differ but OS was superior for EOPC (undefined vs 27.7 months, HR 0.26, p = 0.004). In borderline resectable pts, RFS was similar and OS only numerically superior for EOPC (31.2 vs 17.7 months, p = 0.20). For locally advanced disease, 1L progression free survival (PFS1) was similar and OS was superior for EOPC (27.8 vs 11 months, HR 0.40, p = 0.008). There was no difference in PFS1/OS for metastatic pts. Conclusions: EOPC are fitter, with similar stage at diagnosis as LOPC. EOPC are more likely to receive neoadjuvant chemotherapy and undergo resection when presenting with borderline resectable disease. EOPC receive more treatment and have superior OS, with RFS/PFS1 not statistically different to LOPC.

Psychosocial well-being and supportive care needs of cancer patients and survivors living in rural or regional areas: a systematic review from 2010 to 2021

Purpose

To summarise what is currently known about the psychosocial morbidity, experiences, and needs of people with cancer and their informal caregivers, who live in rural or regional areas of developed countries.

Methods

Eligible studies dating from August 2010 until May 2021 were identified through several online databases, including MEDLINE, EMBASE, PsychINFO, and RURAL (Rural and Remote Health Database). Results were reported according to the PRISMA guidelines and the protocol was registered on PROSPERO (CRD42020171764).

Results

Sixty-five studies were included in this review, including 20 qualitative studies, 41 quantitative studies, and 4 mixed methods studies. Qualitative research demonstrated that many unique psychosocial needs of rural people remain unmet, particularly relating to finances, travel, and accessing care. However, most (9/19) quantitative studies that compared rural and urban groups reported no significant differences in psychosocial needs, morbidity, or quality of life (QOL). Five quantitative studies reported poorer psychosocial outcomes (social and emotional functioning) in urban cancer survivors, while three highlighted poorer outcomes (physical functioning, role functioning, and self-reported mental health outcomes) in the rural group.

Conclusion

Recent research shows that rural people affected by cancer have unique unmet psychosocial needs relating to rurality. However, there was little evidence that rural cancer survivors report greater unmet needs than their urban counterparts. This contrasts to the findings from a 2011 systematic review that found rural survivors consistently reported worse psychosocial outcomes. More population-based research is needed to establish whether uniquely rural unmet needs are due to general or cancer-specific factors.

Systematic Review of Neoadjuvant Immunotherapy for Patients With Non-Small Cell Lung Cancer

There is a paucity of robust clinical evidence for the role of neoadjuvant immunotherapy in patients with resectable non-small cell lung cancer. The primary aim of the study was to identify the available data on the feasibility, safety and efficacy of neoadjuvant immunotherapy. A systematic review was conducted using electronic databases. Relevant studies were identified according to predefined selection criteria. Five relevant publications on 4 completed trials were identified. In most studies, >90% of patients were able to undergo surgery within the planned timeframe after neoadjuvant immunotherapy. There was a high incidence of open thoracotomy procedures, either planned or converted from a planned minimally invasive approach. Mortality ranged from 0 to 5%, but none of the reported deaths were considered directly treatment-related. Morbidities were reported according to adverse events related to neoadjuvant systemic therapy, and postoperative surgical complications. Survival outcomes were limited due to short follow-up periods. Major pathologic response ranged from 40.5 to 56.7%, whilst complete pathologic response of the primary tumor ranged from 15 to 33%. Radiological responses were reported according to RECIST criteria and fluorodeoxyglucose-avidity. This systematic review reported safe perioperative outcomes of patients who underwent resection following neoadjuvant immunotherapy. However, there was a relatively high incidence of open thoracotomy procedures, partly due to the technical challenges associated with increased fibrosis and inflammation of tissue, as well as the more advanced stages of disease in patients enrolled in the studies. Future studies should focus on identifying predictors of pathological response.

Impact of COVID-19 on cancer service delivery: results from an international survey of oncology clinicians

Objectives

To report clinician-perceived changes to cancer service delivery in response to COVID-19.

Design

Multidisciplinary Australasian cancer clinician survey in collaboration with the European Society of Medical Oncology.

Setting

Between May and June 2020 clinicians from 70 countries were surveyed; majority from Europe (n=196; 39%) with 1846 COVID-19 cases per million people, Australia (AUS)/New Zealand (NZ) (n=188; 38%) with 267/236 per million and Asia (n=75; 15%) with 121 per million at time of survey distribution.

Participants

Medical oncologists (n=372; 74%), radiation oncologists (n=91; 18%) and surgical oncologists (n=38; 8%).

Results

Eighty-nine per cent of clinicians reported altering clinical practices; more commonly among those with versus without patients diagnosed with COVID-19 (n=142; 93% vs n=225; 86%, p=0.03) but regardless of community transmission levels (p=0.26). More European clinicians (n=111; 66.1%) had treated patients diagnosed with COVID-19 compared with Asia (n=20; 27.8%) and AUS/NZ (n=8; 4.8%), p<0.001. Many clinicians (n=307; 71.4%) reported concerns that reduced access to standard treatments during the pandemic would negatively impact patient survival. The reported proportion of consultations using telehealth increased by 7.7-fold, with 25.1% (n=108) of clinicians concerned that patient survival would be worse due to this increase. Clinicians reviewed a median of 10 fewer outpatients/week (including non-face to face) compared with prior to the pandemic, translating to 5010 fewer specialist oncology visits per week among the surveyed group. Mental health was negatively impacted for 52.6% (n=190) of clinicians.

Conclusion

Clinicians reported widespread changes to oncology services, in regions of both high and low COVID-19 case numbers. Clinician concerns of potential negative impacts on patient outcomes warrant objective assessment, with system and policy implications for healthcare delivery at large.

Retrospective Evaluation of the Use of Pembrolizumab in Malignant Mesothelioma in a Real-World Australian Population

INTRODUCTION

We investigated the efficacy and toxicity of pembrolizumab in patients with mesothelioma from a real-world Australian population. We aimed to determine clinical factors and predictive biomarkers that could help select patients who are likely to benefit from pembrolizumab.

METHOD

Patients with mesothelioma who were treated with pembrolizumab as part of the Insurance and Care New South Wales compensation scheme were included. Clinical information was collected retrospectively. Tumor biomarkers such as programmed death-ligand 1 (PD-L1), BAP1, and CD3-positive (CD3+) tumor-infiltrating lymphocytes (TILs) were examined using archival formalin-fixed paraffin-embedded tumor samples.

RESULTS

A total of 98 patients were included with a median age of 70 years (range, 46-91 y); 92% were men; 76% had epithelioid subtype; 21% had an Eastern Cooperative Oncology Group (ECOG) performance status of 0. Pembrolizumab was used as second-line or subsequent-line treatment in 94 patients and as first-line treatment in four patients. The overall response rate was 18%, and the disease control rate was 56%. The median progression-free survival (PFS) was 4.8 months (95% confidence interval: 3.6-6.2), and the median overall survival (OS) was 9.5 months (95% confidence interval: 6.6-13.7). Immune-related adverse events occurred in 27% of patients, of which nine (9%) were of grade 3 or higher. In the multivariable analysis, factors independently associated with longer PFS included baseline ECOG status of 0 (median PFS: 12 mo versus 4 mo, p < 0.01) and PD-L1 tumor proportion score of greater than or equal to 1% (median PFS: 6 mo versus 4 mo, p < 0.01). Baseline platelet count of less than or equal to 400 × 109/liter was independently associated with longer PFS and OS (median PFS: 6 mo versus 2 mo, p = 0.05; median OS: 10 mo versus 4 mo, p = 0.01), whereas lack of pretreatment dexamethasone was independently associated with OS but not PFS (median OS: 10 mo versus 3 mo, p = 0.01). The odds of response were higher for patients with baseline ECOG status of 0 (p = 0.02) and with greater than or equal to 5% CD3+ TILs in the tumor (p < 0.01). PD-L1 expression, BAP1 loss, and CD3+ TILs in the stroma were not significantly associated with the overall response rate.

CONCLUSIONS

Immunotherapy is a reasonable treatment option for patients with mesothelioma. Our results are comparable to other clinical trials investigating pembrolizumab in mesothelioma in terms of response. Good performance status assessment remains the most robust predictor for patient outcomes. CD3+ TILs in the tumor may help select patients that are likely to respond to pembrolizumab, whereas factors such as PD-L1 expression, baseline platelet count, and lack of pretreatment dexamethasone may help predict survival outcomes from pembrolizumab treatment.

Rice bran arabinoxylan compound and quality of life of cancer patients (RBAC-QoL): Study protocol for a randomized pilot feasibility trial

Introduction

Rice bran arabinoxylan compound (RBAC) is a nutraceutical for enhancing a depleted immune system during and after cancer treatment. This pilot feasibility trial aims to evaluate the effects of RBAC on cancer patients' quality of life during active treatment, compared to placebo, using a validated questionnaire. Other outcome measures include changes in inflammatory and nutritional status, cytokine profile, and gut microbiota.

Methods/Design

The study will recruit 50 participants from a regional cancer center in Australia. Patients aged 18–70, diagnosed with solid organ cancers stage II and above, and currently undergoing active systemic therapies, are eligible. Random allocation of participants into two groups is stratified based on metastatic status and treatment type. The dosage is either 3 g/day of RBAC or placebo in identical packaging. The participants, study coordinator, and treating oncologists are blinded to the interventions. Data collections are at baseline and at four follow-up sessions, which are six weeks apart (24 weeks). Statistical analysis will involve a protected p-value with multiple dependent values and analyzed by ANOVA with repeated measures on the occasion of testing and with both a full Bonferroni or Sidak corrections applied to protect against Type I errors. Any observed significance warrants further analysis with pairwise comparisons. Analysis of covariance will also be performed to assess any influence of the demographic data, cancer diagnosis, as well as changes in physical activity, dietary habits, and complementary medicine usage. Comparisons of gut microbiota will be based on the analysis of the fecal microbiome using 16S ribosomal ribonucleic acid amplicon sequencing. The proposed research timeline is from October 2018 to May 2022.

Trial registration

ANZCTR. Reg No: ACTRN12619000562178p.

Real-world survival outcomes of using neoadjuvant chemotherapy in pancreatic cancer patients: Findings from the PURPLE clinical registry

e16755

Background: Only a minority of pancreatic cancer patients (pts) are surgical candidates at presentation. Neoadjuvant chemotherapy (NAT) is proposed to increase the proportion of surgical candidates. This study investigates the impact of NAT in routine care of pancreatic cancer. Three cohorts were analysed, patients with early-stage resectable (ER), borderline resectable (BR) and locally advanced (LA) pancreatic cancer. Within these groups, survival outcomes of those undergoing immediate resection (IR) was compared to those receiving NAT with nab-paclitaxel and Gemcitabine (nabPGem) and NAT with FOLFIRINOX. Methods: The PURPLE registry consists of 1492 pancreatic cancer pts from 27 hospitals in Australia, New-Zealand and Singapore, collated between 2016-2019. After exclusion of LA unresectable and metastatic pts (n = 809), 683 pts were included. Kaplan-Meir curves estimated survival between groups with 95% confidence intervals. Multivariable cox proportional hazards models adjusted for age, gender and ECOG performance status. Results: Of 683 pts, 107 received NAT and 576 underwent IR. Those in the NAT group had favourable characteristics, including younger age (mean 63 vs. 66 yrs, p < 0.01) and higher proportion of ECOG 0 vs. ≥1 (64% vs 46%) than those undergoing IR. Of those that received NAT, 64 received FOLFIRINOX and 35 nabPGem. Those receiving FOLFIRINOX were younger (mean: 60 vs. 67 yrs, p < 0.01) and were more likely ECOG 0 compared to those receiving nabPGem (72% vs. 46%, p = 0.02). Resection rates for pts undergoing IR vs. NAT were 88% vs. 50% in ER and 16% vs. 43% in BR. Rates of R0 resection margins in pts undergoing IR vs. NAT were 54% vs. 25% in ER and 6% vs. 21% in BT. Comparing ER to BR, mOS was 29.9 vs. 20.3 mths (HR: 0.54, p < 0.01). Within BR, mOS was 20.3 vs. 17.2 mths for NAT vs. IR (HR: 1.11, p = 0.74). Comparing those receiving FOLFIRINOX vs. nabPGem over all groups, mOS was 22 mths vs. 12 mths (HR: 0.31, p < 0.01). Conclusions: Real-world data confirms the use of NAT remains infrequent in this Asia-Pacific population. The use of FOLFIRINOX was associated with better survival than nabPGem based on this observational study. Improved methods for treatment selection are required. Potential biomarkers including circulating tumor DNA are being explored in the DYNAMIC-Pancreas clinical trial.

Older adults' preferred and perceived roles in decision-making about palliative chemotherapy, decision priorities and information preferences

AIM

Patients with cancer have varied preferences for involvement in decision-making. We sought older adults' preferred and perceived roles in decision-making about palliative chemotherapy; priorities; and information received and desired.

METHODS

Patients ≥65y who had made a decision about palliative chemotherapy with an oncologist completed a written questionnaire. Preferred and perceived decision-making roles were assessed by the Control Preferences Scale. Wilcoxon rank-sum tests evaluated associations with preferred role. Factors important in decision-making were rated and ranked, and receipt of, and desire for information was described.

RESULTS

Characteristics of the 179 respondents: median age 74y, male (64%), having chemotherapy (83%), vulnerable (Vulnerable Elders Survey-13 score ≥ 3) (52%). Preferred decision-making roles (n = 173) were active in 39%, collaborative in 27%, and passive in 35%. Perceived decision-making roles (n = 172) were active in 42%, collaborative in 22%, and passive in 36% and matched the preferred role for 63% of patients. Associated with preference for an active role: being single/widowed (p = .004, OR = 1.49), having declined chemotherapy (p = .02, OR = 2.00). Ranked most important (n = 159) were "doing everything possible" (30%), "my doctor's recommendation" (26%), "my quality of life" (20%), and "living longer" (15%). A minority expected chemotherapy to cure their cancer (14%). Most had discussed expectations of cure (70%), side effects (88%) and benefits (82%) of chemotherapy. Fewer had received quantitative prognostic information (49%) than desired this information (67%).

CONCLUSION

Older adults exhibited a range of preferences for involvement in decision-making about palliative chemotherapy. Oncologists should seek patients' decision-making preferences, priorities, and information needs when discussing palliative chemotherapy.

Patterns of immunotherapy use and management of toxicities in regional and tertiary settings

BACKGROUND

The introduction of the cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) immune checkpoint inhibitors and their subsequent listing on the Pharmaceutical Benefits Scheme for use in metastatic melanomas, renal cell carcinomas and non-small-cell lung cancers has resulted in routine use of these agents in oncology practices, including in regional areas. Although immunotherapeutic agents generally have a favourable toxicity profile compared to chemotherapy, they can provoke immune-related adverse effects (irAE) caused by an unregulated and hyperstimulated immune response. Some of these effects can be serious and life-threatening.

AIMS

To compare the utilisation of immunotherapy and the rates, management and outcomes of irAE between a regional oncology service and a tertiary service.

METHODS

We reviewed the medical records for all patients treated with immunotherapy in the participating services for the 5-year period from 31 July 2012 to 31 July 2017.

RESULTS

Data demonstrated that rates of immunotherapy use are both similar and increasing across the tertiary and regional services. The rates, types and severity of irAE are equivalent and in concordance with pre-existing literature. Immune-related adverse events appear to be identified and treated earlier in the regional service with the corresponding reduction in the duration of immunosuppression and requirement for inpatient management.

CONCLUSION

The use of immunotherapy in a regional setting is safe and equivalent to that of a tertiary centre.

Older adults’ preferred and perceived roles in decision making about palliative chemotherapy: Their decision priorities, and information preferences

11546

Background: We sought older adults’ preferred and perceived roles in decision-making about palliative chemotherapy; their decision-making priorities; and information received and desired. Methods: Patients aged ≥65 years with incurable cancer who had discussed palliative chemotherapy with an oncologist and made a decision about whether or not to receive palliative chemotherapy were invited to complete a written questionnaire. Preferred and perceived decision-making roles were assessed by the Control Preferences Scale (CPS). Associations with preferred decision-making role were examined using Wilcoxon rank sum tests. Factors important in making a decision about chemotherapy, and receipt of and desire for information were described. Results: The 179 respondents had a median age of 74 years (range 65 to 92 years). Most were male (114, 64%) and had chosen to receive chemotherapy (148, 83%). Half (92, 52%) were vulnerable by the Vulnerable Elders Survey-13 (score ≥3). Preferred decision-making roles (n = 173) were active in 39%, collaborative in 27%, and passive in 35%. Perceived decision-making roles (n = 172) were active in 42%, collaborative in 22%, and passive in 36%, and matched the preferred role for 63% of patients. Preference for an active role was associated with being single/widowed (p = 0.004, OR 1.49) and declining chemotherapy (p = 0.02, OR 2). Factors ranked most important when making a decision about chemotherapy (n = 159) were “doing everything possible” (30%), “my doctor’s recommendation” (26%), “my quality of life” (20%), and “living longer” (15%). A minority expected chemotherapy to cure their cancer (14%). Most had discussed expectations of cure (70%), side effects (88%) and benefits (82%) of chemotherapy, though fewer had received quantitative prognostic information (49%) than desired this (67%). Conclusions: Older adults showed varied preferences for involvement in decision-making about palliative chemotherapy, and most played the role that they preferred. To facilitate shared decision-making, oncologists should seek patients’ decision-making preferences, priorities and information needs when discussing palliative chemotherapy.

A multicentre analysis of abiraterone acetate in Canadian patients with metastatic castration-resistant prostate cancer

INTRODUCTON

The COU-AA-301 trial showed that abiraterone acetate (abiraterone), an oral cytochrome p450 CYP17 inhibitor, improved survival for men with metastatic castration-resistant prostate cancer (mCRPC) progressing after docetaxel. To better understand the non-clinical trial experience with abiraterone, we undertook a multicentre retrospective analysis of Canadian mCRPC patients treated with abiraterone.

METHODS

Consecutive patients with mCRPC who received abiraterone post-docetaxel were identified using centralized pharmacy records. These patients came from 5 Canadian tertiary cancer centres. Patients who received abiraterone for approved indications were included. Demographics, prognostic factors, treatment outcomes and adverse events were abstracted.

RESULTS

We included 187 patients who initiated abiraterone between January 2011 and June 2012. The median age at diagnosis and abiraterone start was 65 and 73 years, respectively. Seventy-three (39%) patients had metastatic disease at diagnosis. The Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, 2 and 3 was noted in 17, 96, 39 and 8 patients, respectively. The median prostate-specific antigen (PSA) at abiraterone start was 132, with a median PSA doubling time of 2.8 months. The median follow-up of patients still on active follow-up was 13 months. The proportion of patients achieving a ≥50% PSA reduction was 64/177 (36%). PSA progression-free survival was 3.5 months (95% confidence interval [CI], 3.0, 4.0). Median overall survival from start of abiraterone was 11 months (95% CI, 8.0, 13) and 38 months (95% CI, 31, 41) from date of mCRPC. Anemia and fatigue were the most commonly reported adverse events.

CONCLUSIONS

This study carries the inherent limitations of a retrospective chart review. The outcomes in this series of men treated with abiraterone in a non-trial setting were expected, considering previous clinical trials. Our results, therefore, support the generalizability of the COU-AA-301 study results.

Probing the repulsive core of the nucleon-nucleon interaction via the (4)He(e,e'pN) triple-coincidence reaction

We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830  MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ∼500  MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.

NT-proBNP Changes in Patients with Ascites during Large Volume Paracentesis

Background. N-terminal probrain natriuretic peptide (NT-proBNP) is a hormone involved in the regulation of cardiovascular homeostasis. Changes in serum NT-proBNP during large volume paracentesis (LVP) in patients with ascites have never before been examined. Aims. To determine if significant changes in serum NT-proBNP occur in patients undergoing LVP and the associated clinical correlates in patients with cirrhosis. Method. A total of 45 patients with ascites were prospectively recruited. Serum NT-proBNP, biochemistry, and haemodynamics were determined at baseline and at key time points during and after paracentesis. Results. 34 patients were analysed; 19 had ascites due to cirrhosis and 15 from malignancy. In those with cirrhosis, NT-proBNP decreased by 77.3 pg/mL at 2 L of drainage and 94.3 pg/mL at the end of paracentesis, compared with an increase of 10.5 pg/mL and 77.2 pg/mL in cancer patients at the same time points (P = 0.05 and P = 0.03). Only congestive cardiac failure (CCF) was an independent predictor of significant NT-proBNP changes at the end of drainage in cirrhotic patients (P < 0.01). There were no significant changes in haemodynamics or renal biochemistry for either group. Conclusion. Significant reductions in serum NT-proBNP during LVP occur in patients with cirrhosis but not malignancy, and only comorbid CCF appeared to predict such changes.

A multicenter population-based experience with abiraterone acetate (AA) in patients with metastatic castration resistant prostate cancer (mCRPC)

113

Background: The COU-AA-301 trial showed that abiraterone (AA), an oral cytochrome p450 CYP17 inhibitor, improved survival for men with mCRPC progressing after docetaxel. AA is now a standard treatment in this setting. In order to better understand the non-clinical trial experience with AA, we undertook a multicenter retrospective analysis of patients (pts) treated with AA. Methods: Consecutive pts with mCRPC from 5 tertiary cancer centers in Canada who had received AA post-docetaxel were identified using centralized pharmacy records for each center. Pts who received AA for approved indications or within expanded access programs were included. Demographics, prognostic factors, treatment outcomes and toxicity profiles were collected. Results: One hundred and eighty seven pts, who initiated AA between Jan-2011 and Jun-2012, were included. Median age at diagnosis and AA start was 65 and 73 years. 73 (39%) pts had M1 disease at diagnosis. ECOG 0/1/2/3 was noted in 17/96/39/8 pts. Median PSA at AA start was 132 with a median PSAdt of 2.8 months. 54 (29%) pts received more than 1 prior course of chemotherapy. Median follow up was 20.5 months. Median survival from start of AA was 9.3 months (95% CI, 7.9-12.6). Regional results were: Alberta 14 months (95% CI, 13-18); BC 8.2 months (95% CI, 5.4-9.6); and Ontario 7.3 months (95% CI, 5.7-8.1). Median overall survival from date of mCRPC was 36 months (95% CI, 29-40); in Alberta this was 39 months (95% CI, 29-47); BC 26 months (95% CI, 18-41); and Ontario 33 months (95% CI, 25-41). AA was well tolerated with toxicities comparable to those seen in the trial population, with anemia and fatigue being the most common reported toxicity. Conclusions: This is one of the largest cohorts of men with mCRPC treated with AA in the non-clinical trial setting. Treatment outcomes corroborate with results reported in clinical trials, supporting the effectiveness of AA in an unselected population. A difference in survival outcomes between the different cancer regions can be attributed to differences in time to AA start. Future analyses to evaluate potential prognostic/predictive factors will be undertaken.

Quantitative Analysis of HER2 Receptors Expression In Vivo by Near-Infrared Optical Imaging

Purpose: HER2 overexpression has been associated with a poor prognosis and resistance to therapy in breast cancer patients. However, up to now, quantitative estimates of this important characteristic have been limited to ex vivo ELISA essays of tissue biopsies and/or PET-based analysis. We aim at developing a novel approach in optical imaging, involving specific probes that do not interfere with the binding of the therapeutic agents, thus, excluding competition between therapy and imaging. Affibody-based molecular probes seem to be ideal for in vivo analysis of HER2 receptors using near-infrared optical imaging. To achieve quantification of HER2 receptors and overcome experimental uncertainties, we analyze post-injection temporal variations of the fluorescence intensity in the tumor area.Experimental design: Quantitative in vivo near-infrared imaging uses HER2-specific albumin-binding domain-fused-(ZHER2:342)2 Affibody molecules, labeled with AlexaFluor750 dye, as targeting agents. Subcutaneous tumor xenografts, expressing different levels of HER2 (BT474, MDA-MB361, MCF7, U251), are imaged at different times post-injection. Mathematical modeling allowed assessment of correlation between measured characteristics and HER2 expression levels from ex-vivo assays of the same tumors.Results: Affibody-Alexa Fluor conjugates may be used as a specific near-infrared probe for the non-invasive imaging of HER2-positive tumors, while analysis of the imaging parameters, directly estimated from the sequence of optical images, provides quantitative insight on the HER2 overexpression, as suggested by observed correlation between tumor cell amplification/overexpression of HER2, and these parameters.Conclusions: Method might potentially be employed in clinic for noninvasive monitoring of the HER2 expression variation in response to therapeutic intervention.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5002.

Is MUGA scan necessary in patients with low-risk breast cancer before doxorubicin-based adjuvant therapy? Multiple gated acquisition

Doxorubicin-based chemotherapy in the adjuvant treatment of breast cancer has become standard. Use of doxorubicin is limited by cardiac dysfunction; however, the incidence is dramatically reduced by limiting the dose to less than 550 mg/m(2). Although the cumulative dose in breast cancer is typically 240 mg/m(2), multiple gated acquisition (MUGA) scans are still recommended for determining cardiac functional status in these patients. To examine the need for this practice, we reviewed 296 patients who underwent surgery for breast cancer at Roswell Park Cancer Institute between July 1997 and December 1998. Fifty-nine of 95 (62%) patients receiving doxorubicin-based regimens, and 3 of 39 (7%) receiving nondoxorubicin regimens had pretreatment MUGA scans. The MUGA scans showed normal results in 58 patients and low-normal in 4 (6.5%), with no wall motion abnormalities encountered. There were no cases where doxorubicin was not used because of an abnormal MUGA scan. There were no cardiac complications in the 59 women who received doxorubicin-based chemotherapy. MUGA will screen out few, if any, women under consideration for doxorubicin-based adjuvant therapy; the decision to avoid doxorubicin can be made based on age and preexisting comorbidity. Guidelines recommending routine use of MUGA before the administration of doxorubicin for adjuvant therapy for breast cancer should be reconsidered.

Human genetic disorders, a phylogenetic perspective

When viewed from the perspective of time, human genetic disorders give new insights into their etiology and evolution. Here, we have correlated a specific set of Alu repetitive DNA elements, known to be the basis of certain genetic defects, with their phylogenetic roots in primate evolution. From a differential distribution of Alu repeats among primate species, we identify the phylogenetic roots of three human genetic diseases involving the LPL, ApoB, and HPRT genes. The different phylogenetic age of these genetic disorders could explain the different susceptibility of various primate species to genetic diseases. Our results show that LPL deficiency is the oldest and should affect humans, apes, and monkeys. ApoB deficiency should affect humans and great apes, while a disorder in the HPRT gene (leading to the Lesch-Nyhan syndrome) is unique to human, chimpanzee, and gorilla. Similar results can be obtained for cancer. We submit that de novo transpositions of Alu elements, and saltatory appearances of Alu-mediated genetic disorders, represent singularities, places where behavior changes suddenly. Alus' propensity to spread, not only increased the regulatory and developmental complexity of the primate genome, it also increased its instability and susceptibility to genetic defects and cancer. The dynamic spread not only provided markers of primate phylogeny, it must have actively shaped the course of that phylogeny.

Alu-mediated phylogenetic novelties in gene regulation and development

Differential gene expression lies at the heart of biology and is responsible for all developmental processes, including the growth and differentiation of cells. Perhaps even speciation could be defined as a change in differential gene expression over evolutionary time. The present work is a phylogenetic study of four Alu elements known to have gene regulatory functions in the human. The four elements have been shown to regulate the parathyroid hormone (PTH) gene via a negative calcium-response element, the hematopoietic cell-specific FcepsilonRI-gamma receptor gene via a cis-acting positive/negative regulatory element, the CNS-specific nicotinic acetylcholine receptor alpha3 gene via a cis-acting positive/negative control element, and the T-cell-specific CD8alpha gene via a complex transcriptional regulator. The four Alu elements that impact differential gene expression were found to be differentially distributed among seven primate species (human, chimpanzee, gorilla, orangutan, baboon, rhesus, and macaque) in a way that is congruent with an accepted phylogeny of these species. The results establish a link between gene regulation and the divergence of primates. This evolutionary variation in gene regulation also suggests a novel experimental system to study the very complex transcriptional regulation of gene expression, by studying side-by-side the regulation of the same gene from two primate species that differ in the cis-acting regulatory elements of the gene.

Electronic structure and nonlinear optical properties of model push-pull polyenes with modified indanone groups: a theoretical investigation

Several model polyenes with modified indanone groups were studied by means of density functional theory (DFT) B3LYP/6-31G*, ab initio HF/3-21G* and semiempirical AM1 methods. We investigated the effect of several substituents upon the relationship between the structure, spatial distribution of the highest occupied and the lowest unoccupied pi-MOs, a concept of the global softness and the global hardness as well as both linear and nonlinear polarizabilities for the set of pi-electron chromophores represented by the short-chain model polyene (butadiene) carrying out p-methoxyphenyl group on the one end and several modified indanone groups on the opposite end of the molecule. As probing endocyclic groups used to modify the structure of indanone the following substituents: > CH2; > C=O; > SO2, > C=CH(NO2) and > C=C(CN)2 were selected. The cubic relationship between the polarizability and the global softness was found. The highest polarizabilities (alpha, beta, gamma) are predicted for the derivatives with > C=C(CN)2 group. It was found that the value of beta depends mainly on the difference between dipole moments in the excited and ground states of the molecules. In the case of > SO2 group the results of AMI calculations significantly deviate from relationships found for other derivatives. Experimental IR and Raman spectra of newly synthesized indandione derivative of cinnamaldehyde were compared with computed ones.

Origin and phylogenetic distribution of Alu DNA repeats: irreversible events in the evolution of primates

Over the past 60 million years, or so, approximately one million copies of Alu DNA repeats have accumulated in the genome of primates, in what appears to be an ongoing process. We determined the phylogenetic distribution of specific Alu (and other) DNA repeats in the genome of several primates: human, chimpanzee, gorilla, orangutan, baboon, rhesus, and macaque. At the population level studied, the majority of the repeats was found to be fixed in the primate species. Our data suggest that new Alu elements arise in unique, irreversible events, in a mechanism that seems to preclude precise excision and loss. The same insertions did not arise independently in two species. Once inserted and genetically fixed, the DNA elements are retained in all descendant lineages. The irreversible expansion of Alu s introduces a vector of time into the evolutionary process, and provides realistic (rather than statistical) answers to questions on phylogenies. In contrast to point mutations, the present distribution of individual Alu s is congruent with just one phylogeny. We submit that only irreversible and taxonomically relevant events are at the molecular basis of evolution. Most point mutations do not belong to this category.

The chimpanzee alpha-fetoprotein-encoding gene shows structural similarity to that of gorilla but distinct differences from that of human

The chimpanzee (Pan troglodytes) alpha-fetoprotein (AFP)-encoding gene (AFP) spans 18,867 bp from the transcription start point to the polyadenylation site, and the nucleotide (nt) sequence reveals that the gene is composed of 15 exons, which are symmetrically placed within three domains of AFP. In addition, we report 3121 bp of 5'-flanking sequence and 4886 bp of 3'-flanking sequence. The entire 26,874 bp of contiguous DNA reported here was determined from three overlapping lambda phage clones. The deduced polypeptide chain is composed of a 19-amino-acid (aa) putative leader peptide, followed by 590 aa of the mature protein. The sequence of chimpanzee AFP was compared with those of the previously published human AFP [Gibbs et al., Biochemistry 26 (1987) 1332-1343] and gorilla AFP [Ryan et al., Genomics 9 (1991) 60-72]. At the aa level, the human AFP differs from the chimpanzee at 6 aa positions and from the gorilla at 4 aa positions; the chimpanzee and gorilla differ at 8 aa positions. There are four types of repetitive sequence elements (X, Alu, Xba and Kpn) in the introns and flanking regions of chimpanzee AFP, and they are located in orthologous positions in the human and gorilla AFP. However, one specific Alu and one Xba repeat in introns 4 and 7, respectively, found in human AFP, are absent from orthologous positions in chimpanzee and gorilla AFP. These two repeats represent human-specific novelties that arose from recent DNA transpositions in primate phylogeny.

Complete structure of the human Gc gene: differences and similarities between members of the albumin gene family

The sequence of the human Gc gene, including 4228 base pairs of the 5'-flanking region and 8514 base pairs of the 3' flanking region (55,136 in total), was determined from five overlapping lambda phage clones. The sequence spans 42,394 base pairs from the cap site to the polyadenylation site, and it reveals that the gene is composed of 13 exons, which are symmetrically placed within the three domains of the Gc protein. The first exon is partially untranslated, as is exon 12, which contains the termination codon TAG. Exon 13 is entirely untranslated, but contains the polyadenylation signal AATAAA. Ten central introns split the coding sequence between codon positions 2 and 3 and between codon positions 3 and 1 in an alternating pattern, exactly as has been observed in the structure of the albumin and alpha-fetoprotein genes. The Gc gene has several distinctive features which set it apart from the other members of the family. First, the gene is smaller by two exons, which results in a protein some 130 amino acids shorter than albumin or AFP. This decrease in size may result from the loss of two internal exons during the evolutionary history of the Gc gene. Second, exons 6, 8, 9, and 11 are smaller than their counterparts in albumin or AFP by a total of 8 codons (1, 4, 1, and 2, respectively). Although the mRNA and protein expressed from the Gc gene are significantly smaller, the gene itself is about 2.5 times larger than the other genes of the family.(ABSTRACT TRUNCATED AT 250 WORDS)

Structure of the gorilla alpha-fetoprotein gene and the divergence of primates

The sequence of the gorilla alpha-fetoprotein gene, including 869 base pairs of the 5' flanking region and 4892 base pairs of the 3' flanking region (24,607 in total), was determined from two overlapping lambda phage clones. The sequence extends 18,846 base pairs from the Cap site to the polyadenylation site, and it reveals that the gene is composed of 15 exons, which are symmetrically placed within three domains of alpha-fetoprotein. The deduced polypeptide chain is composed of a 19-amino-acid leader peptide, followed by 590 amino acids of the mature protein. The RNA polymerase II binding site, TATAAAA, and the promoter element, CCAAC, are positioned at -21 and -65 from the Cap site, respectively. The polyadenylation signal, AATAAA, is located in the last exon, which is untranslated. The sequence for the gorilla alpha-fetoprotein gene was compared with that of the previously published human alpha-fetoprotein gene (P. E. M. Gibbs, R. Zielinski, C. Boyd, and A. Dugaiczyk, 1987, Biochemistry 26: 1332-1343). Four types of repetitive sequence elements were found in identical positions in both species. However, one Alu and one Xba DNA repeat within introns 4 and 7, respectively, of the human gene are absent from orthologous positions in the gorilla. The Alu and the Xba DNA repeats probably emerged in the human genome after the human/gorilla divergence and became established novelties in the human lineage. There are 363/21,523 mutational changes between human and gorilla, amounting to 1.69% DNA divergence between the two primate species. The value of 1.69% is lower than the 2.27% obtained from melting temperatures of hybrids between human and gorilla genomic DNA (C. G. Sibley and J. E. Ahlquist, 1984, J. Mol. Evol. 26: 99-121). At the protein level, Homo sapiens differs from Gorilla gorilla only at 4 of 609 amino acid positions (0.66%) in the alpha-fetoprotein sequence. This difference signifies a lower rate of molecular divergence for the alpha-fetoprotein gene in primates, as compared to rodents.

Structure, polymorphism, and novel repeated DNA elements revealed by a complete sequence of the human alpha-fetoprotein gene

The human alpha-fetoprotein gene spans 19,489 base pairs from the putative "Cap" site to the polyadenylation site. It is composed of 15 exons separated by 14 introns, which are symmetrically placed within the three domains of alpha-fetoprotein. In the 5' region, a putative TATAAA box is at position -21, and a variant sequence, CCAAC, of the common CAT box is at -65. Enhancer core sequences GTGGTTTAAAG are found in introns 3 and 4, and several copies of glucocorticoid response sequences AGATACAGTA are found on the template strand of the gene. There are six polymorphic sites within 4690 base pairs of contiguous DNA derived from two allelic alpha-fetoprotein genes. This amounts to a measured polymorphic frequency of 0.13%, or 6.4 X 10(-4)/site, which is about 5-10 times lower than values estimated from studies on polymorphic restriction sites in other regions of the human genome. There are four types of repetitive sequence elements in the introns and flanking regions of the human alpha-fetoprotein gene. At least one of these is apparently a novel structure (designated Xba) and is found as a pair of direct repeats, with one copy in intron 7 and the other in intron 8. It is conceivable that within the last 2 million years the copy in intron 8 gave rise to the repeat in intron 7. Their present location on both sides of exon 8 gives these sequences a potential for disrupting the functional integrity of the gene in the event of an unequal crossover between them. There are three Alu elements, one of which is in intron 4; the others are located in the 3' flanking region. A solitary Kpn repeat is found in intron 3. The Xba and Kpn repeats were only detected by complete sequencing of the introns. Neither X, Xba, nor Kpn elements are present in the related human albumin gene, whereas Alu's are present in different positions. From phylogenetic evidence, it appears that Alu elements were inserted into the alpha-fetoprotein gene at some time postdating the mammalian radiation 85 million years ago.

Further characterization of the polycyclic aromatic hydrocarbon binding properties of the 4S protein

A 4-S protein which specifically binds [3H]benzo(a)pyrene and other polycyclic aromatic hydrocarbons has been investigated in the rat using a hydroxylapatite assay and sucrose gradient analysis. Although there was significant interanimal variation, the specific polycyclic aromatic hydrocarbon binding activity appeared to be highest in 4-week-old male rats and declined with age. The specific [3H]benzo(a)pyrene binding activity was induced after pretreatment with either phenobarbital or isosafrole as evidenced by a 72 and 61% increase, respectively, over untreated controls. No apparent increase in specific binding activity was observed after pretreatment of animals with 3-methylcholanthrene. Pretreatment with either phenobarbital or isosafrole also resulted in the appearance of a small, nonspecific, benzo(a)pyrene binding peak at the 8- to 9-S region in the sucrose density gradients. This 8-S peak was not seen in untreated control animals and represented low affinity, high capacity binding sites. In contrast to the 8-S protein, the 4-S binding protein had low affinity for polychlorinated aromatic compounds such as tetrachlorodibenzodioxin and tetrachlorodibenzofuran. The addition of a 200-fold excess of tetrachlorodibenzofuran to incubations did not displace [3H]benzo(a)pyrene from the 4-S protein. The addition of sodium molybdate to isolation buffers, known to stabilize certain hormone receptors, did not alter the sedimentation coefficient or the specific binding activity of the 4-S protein. These experiments indicate that the 4-S protein does not appear to be a subunit of the 8-S protein. We conclude that in the rat the 4-S protein is distinct from the 8-S protein and the 4-S species may regulate the polycyclic aromatic hydrocarbon-induced expression of aryl hydrocarbon hydroxylase activity.