Constraining the Neutron Star Compactness: Extraction of the ^{23}Al(p,γ) Reaction Rate for the rp Process

The ^{23}Al(p,γ)^{24}Si reaction is among the most important reactions driving the energy generation in type-I x-ray bursts. However, the present reaction-rate uncertainty limits constraints on neutron star properties that can be achieved with burst model-observation comparisons. Here, we present a novel technique for constraining this important reaction by combining the GRETINA array with the neutron detector LENDA coupled to the S800 spectrograph at the National Superconducting Cyclotron Laboratory. The ^{23}Al(d,n) reaction was used to populate the astrophysically important states in ^{24}Si. This enables a measurement in complete kinematics for extracting all relevant inputs necessary to calculate the reaction rate. For the first time, a predicted close-lying doublet of a 2_{2}^{+} and (4_{1}^{+},0_{2}^{+}) state in ^{24}Si was disentangled, finally resolving conflicting results from two previous measurements. Moreover, it was possible to extract spectroscopic factors using GRETINA and LENDA simultaneously. This new technique may be used to constrain other important reaction rates for various astrophysical scenarios.

Photothermal Therapy Promotes Tumor Infiltration and Antitumor Activity of CAR T Cells

Chimeric antigen receptor (CAR)-redirected T lymphocytes (CAR T cells) show modest therapeutic efficacy in solid tumors. The desmoplastic structure of the tumor and the immunosuppressive tumor microenvironment usually account for the reduced efficacy of CAR T cells in solid tumors. Mild hyperthermia of the tumor reduces its compact structure and interstitial fluid pressure, increases blood perfusion, releases antigens, and promotes the recruitment of endogenous immune cells. Therefore, the combination of mild hyperthermia with the adoptive transfer of CAR T cells can potentially increase the therapeutic index of these cells in solid tumors. It is found that the chondroitin sulfate proteoglycan-4 (CSPG4)-specific CAR T cells infused in Nod scid gamma mice engrafted with the human melanoma WM115 cell line have superior antitumor activity after photothermal ablation of the tumor. The findings suggest that photothermal therapy facilitates the accumulation and effector function of CAR T cells within solid tumors.

Cancer Immunotherapy with T Cells Carrying Bispecific Receptors That Mimic Antibodies

Tumors are inherently heterogeneous in antigen expression, and escape from immune surveillance due to antigen loss remains one of the limitations of targeted immunotherapy. Despite the clinical use of adoptive therapy with chimeric antigen receptor (CAR)-redirected T cells in lymphoblastic leukemia, treatment failure due to epitope loss occurs. Targeting multiple tumor-associated antigens (TAAs) may thus improve the outcome of CAR-T cell therapies. CARs developed to simultaneously target multiple targets are limited by the large size of each single-chain variable fragment and compromised protein folding when several single chains are linearly assembled. Here, we describe single-domain antibody mimics that function within CAR parameters but form a very compact structure. We show that antibody mimics targeting EGFR and HER2 of the ErbB receptor tyrosine kinase family can be assembled into receptor molecules, which we call antibody mimic receptors (amR). These amR can redirect T cells to recognize two different epitopes of the same antigen or two different TAAs in vitro and in vivo.

Abstract P4-04-10: Genomic profiling of multifocal breast cancer reveals inter-lesion heterogeneity

Introduction: Multifocal breast cancers are common, and tend to show more aggressive clinical features than unifocal breast cancers. While each foci of multifocal breast cancers with similar histology shares the same hormone and ERBB2 receptor status in most cases, substantial genomic differences among lesions have been reported. We aimed to investigate the potential genomic differences between multifocal breast cancer lesions.

Materials and methods: Twenty-one patients with multifocal breast cancer documented in the resection specimen were included. We selected two lesions with the same histology from each of these 21 patients. Capture-based targeted next generation sequencing was performed using a cancer gene panel consisting of 170 genes for single nucleotide variants (SNV) and small insertions/deletions (Indel), and copy number alterations.

Results: The most frequent mutation was TP53 (38.1%), followed by PIK3CA (28.6%). Pathogenic mutations (SNV and Indel) were detected in 13 of 21 patients, of whom 11 shared oncogenic variants in the two lesions. The remaining two patients had different mutation results in TP53 and PIK3CA, respectively. Genomic heterogeneity of copy number alteration was observed in 6 (28.6%) of 21 patients, including difference of FGFR1 status in two patients and difference of FGFR2 status in one patient.

Conclusion: Despite similar histologic features of multifocal tumors, genomic inter-lesion heterogeneity was identified in about one-fourth of patients. The spatial genomic heterogeneity in multifocal breast cancers needs to be considered in representative sampling and molecular tests for personalized medicine.

Citation Format: Ahn S, Kim HJ, Kang E, Kim E-K, Kim SH, Kim JH, Kim IA, Park SY. Genomic profiling of multifocal breast cancer reveals inter-lesion heterogeneity [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-10.

Abstract P4-03-10: Identifying germline APOBEC3B deletion using hereditary cancer panel in Korean patients with operable breast cancer

Background: APOBEC3B is a cytosine deaminase implicated in host immune defense to virus and mutagenesis in cancer. Germline APOBEC3B deletion is known as risk factors for breast cancer with hypermutation and immune activation from previous database-based studies. This study was aimed to evaluate the incidence of germline APOBEC3B deletion in Korean patients with operable breast cancer.

Method: The copy number variants of germline APOBEC3B deletion was analyzed from leukocyte DNA of 103 breast cancer patients whose bloods were collected in 2009 for pharmacogenomic study at Seoul National University Bundang Hospital. Hybrid-capture based next-generation sequencing panel targeting 53 hereditary cancer genes were used. We also measured tumor infiltrating lymphocytes (TILs) and programmed cell death-ligand 1 (PD-L1) expression in tumor or immune cell with a rabbit monoclonal antibody (E1L3N).

Results: Median age of breast cancer diagnosis was 46 (25-72). In APOBEC3B deletion analysis, 10 (9.7%), 36 (35.0%), and 57 (55.3%) patients were identified as two-copy deletion (A3Bdel/del), one-one copy deletion (A3Bdel/wt) and no deletion (A3Bwt/wt), respectively. In non-APOBEC3B analysis, 9 (8.7%) patients were identified as pathogenic variant: RAD51D(n=1), GJB2(n=1), BRCA1(n=1), BRCA2 (n=2), ATM(n=1), USH2A(n=1), RET(n=1), BARD1(n=1). We observed no significant association between germline APOBEC3B deletion with any clinicopathologic features of breast cancer such as age, family history of cancer, and bilateral breast cancer. Triple-negative subtype was associated with A3Bwt/wt Tumors (35.1% in A3Bwt/wt vs. 5.6% in A3Bdel/wt vs20% in A3Bdel/del; P=0.018). After a median follow-up time of 92.8 months, APOBEC3B deletion was not predictive of recurrence or survival. In patients with sufficient tumor samples for the assessment of TIL (n=63) and PD-1 (n=71), A3Bdel/del tumor was associated with higher TILs (>10%) than other tumor types (6/7 patients in A3Bdel/del vs. 13/24 in A3Bdel/wt vs. 15/32 in A3Bwt/wt: Fisher's exact test in A3Bdel/del, P=0.029). However, PD-L1 expression was not associated with APOBEC3B deletion status (1/7 patients >1% PD-L1 in A3Bdel/del vs. 4/26 in A3Bdel/wt vs. 8/38 in A3Bwt/wt: P=0.901).

Germline APOBEC3B deletion and TILs (n=63) TIL (0-10%)TIL (>10%)TotalA3B(wt/wt)17 (53.1%)15 (46.9%)32A3B(del/wt)11 (45.8%)13 (54.2%)24A3B(del/del)1 (14.3%)6 (85.7%)7

Conclusion: We identified germline APOBEC3B deletion in 9.7% of Korean patients with operable breast cancer. The relationship between A3Bdel/del tumor and high TILs suggests that these tumors might be potential candidates for future immunotherapy.

Citation Format: Kim SH, Koung Jin S, Kim YJ, Ahn S, Park SY, Chae SM, Kang E, Kim E-K, Kim IA, Kim JH. Identifying germline APOBEC3B deletion using hereditary cancer panel in Korean patients with operable breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-03-10.

Antitumor Responses in the Absence of Toxicity in Solid Tumors by Targeting B7-H3 via Chimeric Antigen Receptor T Cells

The high expression across multiple tumor types and restricted expression in normal tissues make B7-H3 an attractive target for immunotherapy. We generated chimeric antigen receptor (CAR) T cells targeting B7-H3 (B7-H3.CAR-Ts) and found that B7-H3.CAR-Ts controlled the growth of pancreatic ductal adenocarcinoma, ovarian cancer and neuroblastoma in vitro and in orthotopic and metastatic xenograft mouse models, which included patient-derived xenograft. We also found that 4-1BB co-stimulation promotes lower PD-1 expression in B7-H3.CAR-Ts, and superior antitumor activity when targeting tumor cells that constitutively expressed PD-L1. We took advantage of the cross-reactivity of the B7-H3.CAR with murine B7-H3, and found that B7-H3.CAR-Ts significantly controlled tumor growth in a syngeneic tumor model without evident toxicity. These findings support the clinical development of B7-H3.CAR-Ts.

Key ^{19}Ne States Identified Affecting γ-Ray Emission from ^{18}F in Novae

Detection of nuclear-decay γ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense γ-ray flux is thought to be annihilation radiation from the β^{+} decay of ^{18}F, which is destroyed prior to decay by the ^{18}F(p,α)^{15}O reaction. Estimates of ^{18}F production had been uncertain, however, because key near-threshold levels in the compound nucleus, ^{19}Ne, had yet to be identified. We report the first measurement of the ^{19}F(^{3}He,tγ)^{19}Ne reaction, in which the placement of two long-sought 3/2^{+} levels is suggested via triton-γ-γ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of 1.5-17 at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.

Rapamycin-insensitive companion of mTOR (RICTOR) amplification defines a subset of advanced gastric cancer and is sensitive to AZD2014-mediated mTORC1/2 inhibition

Background

Targeting oncogenic genomic aberrations is an established therapeutic strategy in multiple tumor types. Molecular classification has uncovered a number of novel targets, and rapamycin-insensitive companion of mTOR (RICTOR) amplification has been identified in lung cancer. Further investigation assessing the therapeutic potential of RICTOR amplification as a novel target across advanced cancers is needed.

Patients and methods

Tumor samples from 640 patients with metastatic solid tumors, primarily gastrointestinal and lung cancers were prospectively subjected to a next-generation sequencing (NGS) assay to identify molecular targets. Samples with NGS-detected RICTOR amplification were confirmed with FISH. A RICTOR-amplified patient-derived cell (PDC) line was generated and used to investigate the effectiveness of selective AKT, mTORC1, and mTORC1/2 inhibition.

Results

NGS identified 13 (2%) of 640 patients with RICTOR-amplified tumors (6 gastric, 3 NSCLC, 1 SCLC, 1 CRC, 1 sarcoma, 1 MUO). Of the 13 patients, seven patients had RICTOR protein overexpression by IHC. The prevalence of RICTOR amplification in gastric cancer by NGS was 3.8% (6/160). FISH testing confirmed amplification (RICTOR/control >2) in 5/13 (38%) of samples, including four gastric cancers and one lung cancer. Treatment of a RICTOR amplified PDC with a selective AKT (AZD5363), selective mTORC1 (everolimus), dual mTORC1/2 (AZD2014), and the multi-target kinase inhibitor pazopanib demonstrated preferential sensitivity to the mTORC1/2 inhibitor (AZD2014). Knockdown of RICTOR reversed PDC sensitivity to AZD2014, validating the importance of RICTOR amplification to the PDC line.

Conclusions

RICTOR amplification is a rare but therapeutically relevant genomic alteration across solid tumors. Our results support further pre-clinical and clinical investigation with AZD2014 in RICTOR amplified gastric cancer and highlights the importance of genomic profiling.

Integration of different criteria for borderline resectable pancreatic cancer using classification tree analysis: the use of radiological tumour-vascular interface in correlation with surgical and pathological outcomes

AIM

To integrate various criteria for borderline resectable pancreatic cancer (BRPC) based on radiological parameters using classification tree analysis.

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived the requirement for informed consent. Two hundred and thirty-five tumour-vein interfaces and 67 tumour-artery interfaces in 245 patients with surgically confirmed pancreatic ductal adenocarcinoma who underwent both preoperative computed tomography (CT) and magnetic resonance imaging (MRI) were assessed by two independent readers. Radiological parameters for evaluation of the tumour-vascular interface were boundary, length of interface, degree of circumferential interface, and contour deformity of affected vessels. Classification tree analysis was performed to determine parameters associated with vascular invasion using pathological and surgical results as the reference standard.

RESULTS

In the classification tree analysis for the tumour-vein interface, contour deformity and degree of circumferential interface were the first and second determining factors, respectively, for both surgical and pathological vascular invasion. For the tumour-artery interface, boundary and degree of circumferential interface were the first and second determining factors for surgical invasion, while contour deformity and length of interface were the first and second determining factors for pathological invasion. The BRPC group of modified criteria arbitrarily formed based on the results had similar surgical (74.1-81.6%) and pathological (54.3-63.3%) venous invasion compared to that of the National Comprehensive Cancer Network (NCCN) criteria, and the lowest surgical (33.3%) and pathological (6.7%) arterial invasion compared with those in previously established criteria for BRPC (43.3-55.6% and 22.2-26.1%, respectively).

CONCLUSION

Various criteria for BRPCs were integrated using classification tree analysis, and a modified criterion for BRPC, which provides satisfactory results, was established.