Neoadjuvant Stereotactic MR-Guided Ablative Radiation Therapy (SMART) and Surgical Outcomes in Patients with Pancreatic Cancer

PURPOSE/OBJECTIVE(S)

The benefit of neoadjuvant radiation therapy for patients undergoing surgery for pancreatic ductal adenocarcinoma (PDAC) remains unclear. Stereotactic MR-guided adaptive radiation therapy (SMART) treatment to ablative doses is a newer technique that is well tolerated and has increased local control in unresectable pancreatic cancer. For resectable pancreatic cancer, neoadjuvant SMART has the potential to decrease local recurrence risk and positive margin rates. However, there is concern for perioperative risks associated with ablative dose treatments. We report the efficacy and safety of surgical resection in patients who have received neoadjuvant SMART at our institution.

MATERIALS/METHODS

We conducted a retrospective analysis of all consecutive patients diagnosed with PDAC who had noted vascular involvement of the celiac axis, superior mesenteric, and/or portal vessels between January 2016 and December 2022 at a single, high-volume, academic institution. Perioperative events were defined according to the Clavien-Dindo classification. The Kaplan Meier method was applied to estimate disease free survival (DFS) and overall survival (OS).

RESULTS

Seventeen patients with PDAC and vessel involvement at time of diagnosis who received SMART were included. Median follow-up time was 14.3 months; all patients underwent surgery, at a median time after radiation of 28 days (range: 15 - 90). Median length of postoperative stay was 7 days (range: 3 - 15). Five patients (29%) underwent vascular resection. Fifteen patients (88%) achieved R0 resection, with two R1 resections noted at the SMA and pancreatic neck respectively. Seven patients (41%) had adverse events attributable to surgery, with the majority being defined as abscess or infection (n = 5; 29%). One (6%) Clavien-Dindo grade III or higher toxicity was observed - a cortical cerebrovascular event following surgery. No major bleeding events requiring surgical intervention were noted. At time of event censorship, there were no observable locoregional failures. The median DFS and OS were not reached; however, 1-year DFS and OS were 62% and 87%, respectively.

CONCLUSION

Neoadjuvant SMART appears to be safe, with low rates of surgical complications and promising outcomes. Further identification of patients for this approach requires additional investigation.

Structural Characterisation Reveals Mechanism of IL-13-Neutralising Monoclonal Antibody Tralokinumab as Inhibition of Binding to IL-13Rα1 and IL-13Rα2

Interleukin (IL)-13 is a pleiotropic T helper type 2 cytokine frequently associated with asthma and atopic dermatitis. IL-13-mediated signalling is initiated by binding to IL-13Rα1, which then recruits IL-4Rα to form a heterodimeric receptor complex. IL-13 also binds to IL-13Rα2, considered as either a decoy or a key mediator of fibrosis. IL-13-neutralising antibodies act by preventing IL-13 binding to IL-13Rα1, IL-4Rα and/or IL-13Rα2. Tralokinumab (CAT-354) is an IL-13-neutralising human IgG4 monoclonal antibody that has shown clinical benefit in patients with asthma. To decipher how tralokinumab inhibits the effects of IL-13, we determined the structure of tralokinumab Fab in complex with human IL-13 to 2 Å resolution. The structure analysis reveals that tralokinumab prevents IL-13 from binding to both IL-13Rα1 and IL-13Rα2. This is supported by biochemical ligand-receptor interaction assay data. The tralokinumab epitope is mainly composed of residues in helices D and A of IL-13. It is mostly light chain complementarity-determining regions that are driving paratope interactions; the variable light complementarity-determining region 2 plays a key role by providing residue contacts for a network of hydrogen bonds and a salt bridge in the core of binding. The key residues within the paratope contributing to binding were identified as Asp50, Asp51, Ser30 and Lys31. This study demonstrates that tralokinumab prevents the IL-13 pharmacodynamic effect by binding to IL-13 helices A and D, thus preventing IL-13 from interacting with IL-13Rα1 and IL-13Rα2.

Epitope mapping and key amino acid identification of anti-CD22 immunotoxin CAT-8015 using hybrid β-lactamase display

Monoclonal antibodies are a commercially successful class of drug molecules and there are now a growing number of antibodies coupled to toxic payloads, which demonstrate clinical efficacy. Determining the precise epitope of therapeutic antibodies is beneficial in understanding the structure-activity relationship of the drug, but in many cases is not done due to the structural complexity of, in particular, conformational protein epitopes. Using the immunotoxin CAT-8015 as a test case, this study demonstrates that a new methodology, hybrid β-lactamase display, can be employed to elucidate a complex epitope on CD22. Following insertion of random CD22 gene fragments into a permissive site within β-lactamase, proteins expressed in Escherichia coli were first screened for correct folding by resistance to ampicillin and then selected by phage display for affinity to CAT-8015. The optimal protein region recognised by CAT-8015 could then be used as a tool for fine epitope mapping, using alanine-scanning analysis, demonstrating that this technology is well suited to the rapid characterisation of antibody epitopes.

LPS-induced liver injury in D-galactosamine-sensitized mice requires secreted TNF-alpha and the TNF-p55 receptor

Lipopolysaccharide and D-galactosamine induced lethality and apoptotic liver injury is dependent on endogenously produced tumor necrosis factor (TNF)-alpha. The present study was undertaken to determine whether membrane-associated or secreted TNF-alpha signaling through the p55 or p75 receptor was responsible for survival and hepatic injury after lipopolysaccharide administration in D-galactosamine-sensitized mice. Transgenic mice expressing null forms of TNF-alpha, the p55 and p75 receptor, and mice expressing only a cell-associated form of TNF-alpha were challenged with 8 mg D-galactosamine and 100 ng lipopolysaccharide. Mortality and apoptotic liver injury were only seen in wild-type and p75 knockout mice. p75 Knockout mice had significantly higher concentrations of plasma TNF-alpha than any other experimental group (P </= 0.05) and tended to have the highest mortality and liver injury. In contrast, p55 and TNF-alpha knockout mice and animals expressing only a cell-associated form of TNF-alpha exhibited no mortality or liver injury. We conclude that survival and apoptotic liver injury in response to lipopolysaccharide and D-galactosamine are dependent exclusively on secreted TNF-alpha signaling through the p55 receptor.

Molecular cloning of the gene for interleukin-1beta from Xenopus laevis and analysis of expression in vivo and in vitro

The Xenopus cDNA for interleukin-1beta (IL-1B) was cloned and sequenced. The gene contains 1,462 nucleotides that translate in a single reading frame to give a predicted 283-amino acid IL-1beta molecule. The translated molecule contains a single potential glycosylation site, a readily identifiable IL-1 family signature, and has highest homology to chicken IL-1beta by phylogenetic tree analysis and sequence similarity. It lacks a signal peptide in common with other known IL-1B genes, and lacks a clear ICE (caspase) cut site in common with other nonmammalian IL-1B genes sequenced to date. RT-PCR was used to study sites of IL-1B transcript expression, 24 h following injection of lipopolysaccharide (LPS). Expression was detected in the brain, liver, kidney, and spleen, with expression weakest in the brain and strongest in the spleen. No transcript expression was detectable following injection of saline. Northern blot analysis was used to quantify the induction of IL-1B expression in splenocytes following in vivo or in vitro stimulation with LPS. The results are discussed in relation to the potential role of IL-1beta in amphibian immune responses.

Xenopus NK cells identified by novel monoclonal antibodies

Early-thymectomized (Tx) Xenopus frogs, which are permanently deficient in T cells, are used as a model sytem for the characterization of novel monoclonal antibodies (mAb) which identify candidate NK cells at the amphibian level of evolution. Hybridomas, generated from mice immunized with splenocytes from Tx Xenopus following B cell and thrombocyte depletion, were screened by flow cytometry. Three mAb (1F8, 4D4 and 1G5) were identified that stained increased proportions of splenocytes from Tx compared with control frogs. These mAb identified lymphoid populations from Xenopus spleen, liver and gut which, after 48 h culture in growth factor-rich medium, exhibited spontanous killing of MHC-deficient allotumor targets. mAb-defined splenocytes also rapidly induced apoptosis of such tumor targets. Dual color analysis confirmed that NK cells are neither T nor B cells. Cytospins of splenocytes isolated with anti-NK mAb revealed large lymphoid cells with distinct pseudopodia. Immunohistology indicated each anti-NK mAb routinely labeled cells within the gut epithelium but NK cells were difficult to visualize in spleen sections. Western blotting of spleen, liver and intestinal lysates subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that 1G5 reacted strongly with protein bands of approximately 70 - 85 kDa, whereas mAb 1F8 and 4D4 stained less intensely, but identified similar protein bands.

Androgen receptor polymorphisms: association with prostate cancer risk, relapse and overall survival

Several reports have suggested that one or both of the trinucleotide repeat polymorphisms in the human androgen receptor (hAR) gene, (CAG)n coding for polyglutamine and (GGC)n coding for polyglycine, may be associated with prostate cancer risk; but no study has investigated their association with disease progression. We present here a study of both hAR trinucleotide repeat polymorphisms not only as they relate to the initial diagnosis but also as they are associated with disease progression after therapy. Lymphocyte DNA samples from 178 British Caucasian prostate cancer patients and 195 control individuals were genotyped by PCR for the (CAG)n and (GGC)n polymorphisms in hAR. Univariate Cox proportional hazard analysis indicated that stage, grade and GGC repeat length were individually significant factors associated with disease-free survival (DFS) and overall survival (OS). The relative risk (RR) of relapse for men with more than 16 GGC repeats was 1.74 (95% CI 1. 08-2.79) and of dying from any cause, 1.98 (1.13-3.45). Adjusting for stage and grade, GGC effects remained but were not significant (RR(DFS)= 1.60, p = 0.052; RR(OS)= 1.65, p = 0.088). The greatest effects were in stage T1-T2 (RR(DFS)= 3.56, 95% CI 1.13-11.21) and grade 1 (RR(DFS)= 6.47, 95% CI 0.57-72.8) tumours. No differences between patient and control allele distributions were found by odds-ratio analysis, nor were trends with stage or grade evident in the proportion of short CAG alleles. Non-significant trends with stage and grade were found in the proportion of short GGC alleles. The (GGC)n polymorphism in this population is a significant predictor of disease outcome. Since the (GGC)(n) effect is strongest in early-stage tumours, this marker may help forecast aggressive behaviour and could be used to identify those patients meriting more radical treatment.

Internet course on total quality management

The Internet provides new opportunities to information-based industries such as universities. If a vast majority of potential customers of our programs have access to the Internet, then it is conceivable that many universities will begin teaching Internet courses and that such courses could, in many cases, replace or at least augment existing face-to-face classroom activities. This paper is an account of one such course at Cleveland State University and the type of policy issues raised by the course at this institution.

T-cell and natural killer cell development in thymectomized Xenopus

The Xenopus early-thymectomy model system is used to investigate the extent to which the thymus controls T-cell development and to probe the evolution of natural killer (NK) cells. Loss of T-cell function following thymectomy, together with the paucity of cells expressing monoclonal antibody-defined T-cell surface markers, and greatly reduced expression of T-cell receptor beta transcripts in spleen, liver and intestine, indicate that T-cell development in minimal in the absence of the thymus. Our findings therefore mitigate against the idea that a substantial extrathymic pathway of T-cell development exists in early vertebrate evolution. Rather, they suggest that in this amphibian representative T cells are predominately thymus dependent. In vitro studies with control and thymectomized Xenopus splenocytes reveal that a non-T/non-B population and also two T-cell subsets all display natural cytotoxicity towards allogeneic thymus lymphoid tumour cells (which are deficient in MHC antigen expression). Since Xenopus thymectomized early in larval development are permanently deficient in T cells, they may provide a useful phylogenetic model for the study of NK cells.

Stereotactic core biopsy reduces the reexcision rate and the cost of mammographically detected cancer

The management of patients with mammographic abnormalities is rapidly shifting from needle-localized surgical biopsy (NLB) to stereotactic core biopsy (SCB). The precise role of SCB in the management of nonpalpable breast cancer remains to be defined. The purpose of this study was to compare SCB to NLB in the diagnosis of mammographically detected breast cancer in women who underwent breast-conserving surgery. The records of all patients with nonpalpable breast cancer who underwent breast-conserving surgery from 1/1/95 to 6/1/97 were analyzed with respect to method of diagnosis, time interval from detection to diagnosis and breast-conserving surgery, volume of breast tissue excised, margin status and reexcision rate, number of surgical procedures, and total charges and costs per patient. During a 30-month period, 117 patients with nonpalpable breast cancer underwent breast-conserving surgery. The diagnosis was made by NLB in 69 patients and SCB in 48 patients. The time from detection to diagnosis and breast-conserving surgery was 1.7 +/- 0.5 and 8.1 +/- 1.2 days for SCB patients and 6. 8 +/- 1.3 and 16.9 +/- 2.3 days for NLB patients (P < 0.01). The volume of breast tissue removed was 117.9 +/- 5.6 cm3 for SCB patients versus 75.2 +/- 2.9 cm3 for NLB patients (P < 0.01). Three SCB patients (6%) had positive margins, while 38 NLB patients (55%) had positive margins (P < 0.01). Only 1 SCB patient (2%) was reexcised, while 34 NLB patients (50%) were reexcised (P < 0.01). Eighty-nine percent of SCB patients had a single surgical procedure compared to 39% of NLB patients (P < 0.001). Patients who underwent SCB had reduced total charges and total costs per patient compared to NLB patients ($11,700 +/- $554 and $3537 +/- $167 per SCB patient versus $15,654 +/- $706 and $4853 +/- $198 per NLB patient, P < 0. 0001). Stereotactic core biopsy shortens the time from detection at mammography to diagnosis and breast-conserving therapy, permits appropriate discussion of treatment alternatives, reduces the positive margin rate and reexcision rate, and may represent a significant cost savings in the management of nonpalpable breast cancer.

Formation of the 37-kD protein-acetaldehyde adduct in primary cultured rat hepatocytes exposed to alcohol

We have previously reported that a 37-kD liver protein formed an adduct with acetaldehyde in vivo when rats were fed alcohol chronically. To understand the mechanism of the formation of this protein-acetaldehyde adduct, rat hepatocytes in primary culture were treated with ethanol in vitro for several days. When cultured in hormone-enriched and trace metal-enriched Waymouth's medium, alcohol dehydrogenase activities in hepatocytes decreased only about 30% during 6 days of culture. At the end of the specified time, protein extracts of hepatocytes were immunotransblotted with rabbit immunoglobulin G that recognized acetaldehyde adduct as an epitope. The 37-kD protein-acetaldehyde adduct band could be detected within 3 days in cells that had been treated with alcohol at a steady-state concentration as low as 5 mmol/L. Although the maximal intensity was obtained at approximately 10 to 40 mmol/L ethanol, addition of cyanamide (an inhibitor of aldehyde dehydrogenase) further increased the intensity of this protein-acetaldehyde adduct band by more than twofold. A good correlation existed between acetaldehyde concentration in the medium and the intensity of the 37-kD protein-acetaldehyde adduct band. Formation of the 37-kD liver protein-acetaldehyde adduct is thus dependent on acetaldehyde, and the 37-kD protein is apparently unusually susceptible to chemical modification by acetaldehyde.