Abstract PD2-08: Serial genomic profiling reveals molecular mechanisms of breast cancer resistance to palbociclib

CDK4/6 inhibitors such as palbociclib in combination with endocrine therapy (ET) have remarkablyimproved the outcome of patients with ER+/HER2- metastatic breast cancer (MBC). However, manypatients are intrinsically resistant to CDK4/6i therapy, and those who respond eventually acquireresistance. Although high baseline CCNE1 expression and rare alterations in RB1 and FAT1 geneshave been shown to be associated with CDK4/6i resistance, the molecular mechanisms of CDK4/6iresistance are complex and remain poorly understood. To better understand and overcome CDK4/6iresistance, we performed multi-omics profiling of paired tumor biopsies from ER+/HER2- MBCpatients treated with palbociclib combined with ET. Tumor biopsies taken at pre-treatment, on-treatment, and progressive disease (PD) from 71 patients were profiled using whole-exomesequencing (WES), whole-transcriptome sequencing (RNA-Seq) and IHC analysis. Ourcomprehensive analysis identified several tumor intrinsic molecular markers associated with worsePFS, including the Luminal B subtype (p=0.012, HR=2.593), BRCA1/2 pathogenic mutation (p=0.012,HR=2.67) and mutation signatures linked to APOBEC enzymatic activity (p=0.002, HR=3.19).Conversely, the estrogen response signature (p=0.006, HR=0.43) was associated with favorableprognosis. Unsupervised analysis revealed a cluster of tumors enriched in homologousrecombination deficiency (HRD) linked genomic scars that was associated with poor prognosis(p=0.005, HR=2.49). Of note, these HRD-high tumors responded even more poorly to treatment whenco-occurring with TP53 somatic mutations. Integrative analysis further identified three poorprognosis clusters (IC2-4) enriched in Luminal B, proliferative and HRD features when compared tothe favorable prognosis cluster (IC1).Comparing baseline vs. PD samples, we observed a pattern of post-treatment enrichment for the poorprognosis markers. In addition, breast cancer-associated genes such as BRCA1/2, TP53 and PTENharbored a higher prevalence of genomic alterations including somatic mutation, amplification,. deletion and gene fusion at PD. Cell cycle gene expression and signatures also markedly increased atPD compared to baseline whereas estrogen response signatures decreased. Upon diseaseprogression, tumors had frequently switched to molecular subtypes with aggressive and estrogenindependent characteristics, demonstrating high plasticity in response to CDK4/6i and ET treatment.These patterns of acquired resistance were validated by IHC analysis of cyclins E1 and E2, Ki67 andpRb. To investigate the genomic alterations responsible for acquired resistance, we compared 21paired baseline and PD samples. We observed that PD-specific RB1 loss-of-function events occurredwith higher prevalence than previously reported, underscoring a major role of cell cycle de-regulation in conferring resistance to CDK4/6 inhibition. In this prospective longitudinal multi-omicsstudy, we identified novel candidate biomarkers that can be used to improve prediction of responseto CDK4/6i. In addition, we derived new insights into the molecular mechanisms of drug resistanceto palbociclib plus ET that will help guide therapeutic strategies and drug development inHR+/HER2− MBC.

Citation Format: Zhengyan Kan, Seock-Ah Im, Kyunghee Park, Ji Wen, Kyung-Hun Lee, Yoon-La Choi, Won-Chul Lee, Ahrum Min, Vinicius Bonato, Seri Park, Sripad Ram, Dae-Won Lee, Ji-Yeon Kim, Su Kyeong Lee, Won-Woo Lee, Jisook Lee, Miso Kim, Scott L. Weinrich, Han Suk Ryu, Tae Yong Kim, Stephen Dann, Diane Fernandez, Jiwon Koh, Song Yi Park, Shibing Deng, Eric Powell, Rupesh Kanchi Ravi, Jadwiga Bienkowska, Paul A. Rejto, Woong-Yang Park, Yeon Hee Park. Serial genomic profiling reveals molecular mechanisms of breast cancer resistance to palbociclib [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD2-08.

Prognostic significance of natural killer cell-associated markers in gastric cancer: quantitative analysis using multiplex immunohistochemistry

Background

Natural killer (NK) cells mediate the anti-tumoral immune response as an important component of innate immunity. The aim of this study was to investigate the prognostic significance and functional implication of NK cell-associated surface receptors in gastric cancer (GC) by using multiplex immunohistochemistry (mIHC).

Methods

We performed an mIHC on tissue microarray slides, including 55 GC tissue samples. A total of 11 antibodies including CD57, NKG2A, CD16, HLA-E, CD3, CD20, CD45, CD68, CK, SMA, and ki-67 were used. CD45 + CD3-CD57 + cells were considered as CD57 + NK cells.

Results

Among CD45 + immune cells, the proportion of CD57 + NK cell was the lowest (3.8%), whereas that of CD57 + and CD57- T cells (65.5%) was the highest, followed by macrophages (25.4%), and B cells (5.3%). CD57 + NK cells constituted 20% of CD45 + CD57 + immune cells while the remaining 80% were CD57 + T cells. The expression of HLA-E in tumor cells correlated with that in tumoral T cells, B cells, and macrophages, but not CD57 + NK cells. The higher density of tumoral CD57 + NK cells and tumoral CD57 + NKG2A + NK cells was associated with inferior survival.

Conclusions

Although the number of CD57 + NK cells was lower than that of other immune cells, CD57 + NK cells and CD57 + NKG2A + NK cells were significantly associated with poor outcomes, suggesting that NK cell subsets play a critical role in GC progression. NK cells and their inhibitory receptor, NKG2A, may be potential targets in GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03203-8.

An unusual case of microsatellite instability-high/deficient mismatch repair (MSI-H/dMMR) diffuse large B-cell lymphoma revealed by targeted gene sequencing

Microsatellite instability-high/deficient mismatch repair (MSI-H/dMMR) status has been approved as a tissue-agnostic biomarker for immune checkpoint inhibitor therapy in patients with solid tumors. We report the case of an MSI-H/dMMR diffuse large B-cell lymphoma (DLBCL) identified by targeted gene sequencing (TGS). A 90-year-old female who presented with vaginal bleeding and a large mass in the upper vagina was diagnosed with germinal center-B-cell-like DLBCL, which recurred at the uterine cervix at 9 months after chemotherapy. Based on TGS of 121 lymphoma-related genes and the LymphGen algorithm, the tumor was classified genetically as DLBCL of EZB subtype. Mutations in multiple genes, including frequent frameshift mutations, were detected by TGS and further suggested MSI. The MSI-H/dMMR and loss of MLH1 and PMS2 expression were determined in MSI-fragment analysis, MSI real-time polymerase chain reaction, and immunohistochemical tests. This case demonstrates the potential diagnostic and therapeutic utility of lymphoma panel sequencing for DLBCL with MSI-H/dMMR.

Clinicopathologic implication of PD-L1 gene alteration in primary adrenal diffuse large B cell lymphoma

Background

Primary adrenal (PA) diffuse large B cell lymphoma (DLBCL) was previously reported as an aggressive subset of DLBCL, but its genetic features were not sufficiently characterized. From our previous study of DLBCL with programmed death-ligand 1 (PD-L1) gene alterations, we focused on PD-L1 gene alterations in PA-DLBCL with clinicopathologic implications.

Methods

We performed fluorescence in situ hybridization for PD-L1 gene translocation and amplification in PA-DLBCL (n = 18) and comparatively analyzed clinicopathologic characteristics with systemic non-adrenal (NA)-DLBCL (n = 90).

Results

PA-DLBCL harbored distinctive features (vs. NA-DLBCL), including high international prognostic index score (3–5) (72% [13/18] vs. 38% [34/90], p = .007), poor Eastern Cooperative Oncology Group performance score (≥ 2) (47% [7/15] vs. 11% [10/90], p = .003), elevated serum lactate dehydrogenase (LDH) (78% [14/18] vs. 51% [44/87], p = .035) and MUM1 expression (87% [13/15] vs. 60% [54/90], p = .047). Moreover, PA-DLBCL showed frequent PD-L1 gene alterations (vs. NA-DLBCL) (39% [7/18] vs. 6% [5/86], p = .001), including translocation (22% [4/18] vs. 3% [3/87], p = .016) and amplification (17% [3/18] vs. 2% [2/87], p = .034). Within the PA-DLBCL group, PD-L1 gene–altered cases (vs. non-altered cases) tended to have B symptoms (p = .145) and elevated LDH (p = .119) but less frequent bulky disease (≥ 10 cm) (p = .119). In the survival analysis, PA-DLBCL had a poor prognosis for overall survival (OS) and progression-free survival (PFS) (vs. NA-DLBCL; p = .014 and p = .004). Within the PA-DLBCL group, PD-L1 translocation was associated with shorter OS and PFS (p < .001 and p = .012).

Conclusions

PA-DLBCL is a clinically aggressive and distinct subset of DLBCL with frequent PD-L1 gene alterations. PD-L1 gene translocation was associated with poor prognosis in PA-DLBCL.

Expression of the immune checkpoint receptors PD-1, LAG3, and TIM3 in the immune context of stage II and III gastric cancer by using single and chromogenic multiplex immunohistochemistry

We sought to determine the clinicopathological significance of PD-1, LAG3, and TIM3 in gastric cancer (GC) by examining their expression and immune context. Immunohistochemistry (IHC) for PD-1, TIM3, LAG3, and tumor-infiltrating immune cell (TIIC) markers was performed in 385 stage II/III GCs. Epstein-Barr virus (EBV) and microsatellite stability (MSI) testing were performed for molecular classification. Chromogenic multiplex IHC (mIHC) for PD1, TIM3, LAG3, CD3, CD8, FOXP3, CD68, and cytokeratin was performed in 58 of the total samples. PD-1, LAG3, and TIM3 expression in TIICs was observed in 91 (23.6%), 193 (50.1%), and 257 (66.8%) GCs by single IHC, respectively. The expression was associated with EBV⁺ and MSI-H molecular subtypes (p ≤ 0.001). A positive expression of LAG3 in the invasive margin of the tumor was associated with better prognosis in univariate (p = .020) and multivariate (p = .026) survival analyses. The expression of different immune checkpoint receptors (ICRs) was significantly positively correlated. Dual or triple ICR expression was more frequent in high PD-1 and TIM3 density groups than in low-density groups by mIHC (all p ≤ 0.05). ICRs were mainly expressed in CD3⁺CD8⁺ and CD3⁺CD8⁻ T cells. Fifty-eight GCs were classified into three groups by clustering analysis based on mIHC, and the group with the highest ICR expression in TIICs showed significantly better outcomes in progression-free survival (p = .020). In GC, PD-1, LAG3, and TIM3 expression is positively correlated and associated with better prognosis. Our study provides information for the application of effective immune checkpoint inhibitors against GC.

Marked differences in local bone remodelling in response to different marrow stimulation techniques in a large animal

Marrow stimulation, including subchondral drilling and microfracture, is the most commonly performed cartilage repair strategy, whereby the subchondral bone plate is perforated to release marrow-derived cells into a cartilage defect to initiate repair. Novel scaffolds and therapeutics are being designed to enhance and extend the positive short-term outcomes of this marrow stimulation. However, the translation of these newer treatments is hindered by bony abnormalities, including bone resorption, intralesional osteophytes, and bone cysts, that can arise after marrow stimulation. In this study, three different marrow stimulation approaches - microfracture, subchondral drilling and needle-puncture - were evaluated in a translationally relevant large-animal model, the Yucatan minipig. The objective of the study was to determine which method of marrow access (malleted awl, drilled Kirschner wire or spring-loaded needle) best preserved the underlying subchondral bone. Fluorochrome labels were injected at the time of surgery and 2 weeks post-surgery to capture bone remodelling over the first 4 weeks. Comprehensive outcome measures included cartilage indentation testing, histological grading, microcomputed tomography and fluorochrome imaging. Findings indicated that needle-puncture devices best preserved the underlying subchondral bone relative to other marrow access approaches. This may relate to the degree of bony compaction occurring with marrow access, as the Kirschner wire approach, which consolidated bone the most, induced the most significant bone damage with marrow stimulation. This study provided basic scientific evidence in support of updated marrow stimulation techniques for preclinical and clinical practice.

153 Age and the Extent of Chest Radiographic Findings in Hospitalized Patients with COVID 19

Introduction

Since the emergence of COVID 19 in December 2019, its clinical and radiological features are still being discovered and their prognostic implications evaluated. Chest X-ray (CXR) typically shows patchy or diffuse asymmetric airspace opacities. Regardless of the different classifications of radiological findings that have been used, it is becoming clear that multi-lobar changes in the lungs are associated with poorer outcomes than single lobar involvement or minimal/no radiological abnormalities.

Aim: To assess the correlation of age with the extent of CXR findings in hospitalized COVID 19 patients.

Methods

A retrospective, cross-sectional analysis was carried out on inpatients with RT-PCR confirmed COVID 19. Chest X-ray findings were classified as minimal/no radiological changes, single lobar opacification and multi-lobar changes (involving 2 or more lobes and/or ARDS changes). SPSS 26 software was used for statistical analysis. Spearman’s correlation and linear regression were used to assess correlation.

Results

211 patients were included in the analysis; 124 males and 87 females. Mean age of the patients was 72.4 years; SD +/−16.15. There was significant positive correlation between age and degree and extent of radiological changes in all patients (r = 0.367; p &lt; 0.01). This correlation persisted even when broken down by gender (r = 0.448; p &lt; 0.01) for males and (r = 0.322; p &lt; 0.01) for females. Discussion: Older age has been repeatedly reported as a risk factor for poor prognosis in COVID 19. The main findings of COVID-19 on CXR are those of atypical or organizing pneumonia. Older people tend to have more extensive involvement of the lungs. There could be many explanations for the CXR correlation with age including the diminished cardiovascular reserve with ageing, the accumulation of comorbidities and decreased or abnormal immune response.

Conclusion

Age significantly correlate with the extent of chest radiographic findings in inpatients with COVID 19.

A case of concomitant EGFR/ALK alteration against a mutated EGFR background in early-stage lung adenocarcinoma

Rare cases of lung adenocarcinoma (LUAD) with concomitant epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) translocation have been reported. However, their clonal and evolutional relationship remains unclear. We report a case of early-stage EGFR-mutated LUAD with a focal concomitant EGFR/ALK alteration. A 63-year-old male underwent lobectomy to remove a 1.9-cm-sized lung nodule, which was diagnosed with EGFR-mutated LUAD. ALK immunohistochemistry (IHC) showed focal positivity within the part of the tumor characterized by lepidic pattern, also confirmed by fluorescence in-situ hybridization (FISH). Targeted next-generation sequencing was performed separately on the ALK IHC/FISH-positive and -negative areas. EGFR L833V/L858R mutations were detected in both areas, whereas EML4 (echinoderm microtubule-associated protein-like 4)-ALK translocations was confirmed only in the ALK IHC/FISH-positive area, suggesting the divergence of an EGFR/ALK co-altered subclone from the original EGFR-mutant clone. Our study suggests that concurrent alterations of EGFR and ALK can arise via divergent tumor evolution, even in the relatively early phases of tumorigenesis.

Tryptophanyl-tRNA Synthetase Sensitizes Hormone Receptor-Positive Breast Cancer to Docetaxel-Based Chemotherapy

Purpose

A relatively low response to chemotherapy has been reported for hormone receptor (HR)-positive breast cancer. In this study, we investigated the role of tryptophanyl-transfer RNA synthetase (WARS) in the chemotherapeutic response of HR-positive breast cancer.

Methods

Pre-chemotherapeutic needle biopsy samples of 45 HR-positive breast cancer patients undergoing the same chemotherapeutic regimen were subjected to immunohistochemistry. To investigate the biological functions of WARS in HR-positive breast cancer, we conducted cell viability assay, flow cytometry analysis, caspase activity assay, Quantitative real-time polymerase chain reaction, and western blotting using WARS gene-modulated HR-positive breast cancer cells (T47D, ZR-75-1, and MCF7).

Results

WARS overexpression in HR-positive breast cancer patients showed a significant correlation with favorable chemotherapy response. Downregulation of WARS increased cell viability following docetaxel treatment in tumor cell lines. On the other hand, WARS overexpression sensitized the therapeutic response to docetaxel. Additionally, downregulation of WARS caused a decrease in the number of apoptotic cell populations by docetaxel. Poly (ADP-ribose) polymerase cleavage and caspase 3/7 activity were increased in docetaxel-treated tumor cells with WARS overexpression.

Conclusion

Our results suggest that WARS might be a potential predictor for chemotherapy response in patients with HR-positive breast cancer as well as a novel molecular target to improve chemosensitivity.

Immunophenotypic Landscape and Prognosis of Diffuse Large B-Cell Lymphoma with MYC/BCL2 Double Expression: An Analysis of A Prospectively Immunoprofiled Cohort

Simple Summary

Diffuse large B-cell lymphoma (DLBCL) with MYC/BCL2 double-expression (DE), a recently proposed poor prognostic group, can be easily identified by immunohistochemistry in routine clinical practice. However, clinical outcomes of DE-DLBCL patients vary immensely after R-CHOP immunochemotherapy and prognostic impact of MYC/BCL2-DE was conflicting according to the cell-of-origin, i.e., between germinal center-B-cell (GCB)- and non-GCB-DLBCLs. This implies the heterogeneity within DE-DLBCLs and emphasizes a need for proper risk stratification to select the patients who require more intensive therapy. By analyzing a prospectively immunoprofiled cohort of consecutively diagnosed DLBCL patients, we confirmed the poor prognostic value of MYC/BCL2-DE in DLBCL patients treated with R-CHOP irrespective of the cell-of-origin and international prognostic index. DE-DLBCLs with a concurrent risk factor, especially, elevated serum lactate dehydrogenase (LDH), had the worst survival and DE-DLBCL patients with normal LDH had clinical outcomes similar to those of non-DE-DLBCL patients. Risk stratification of DE-DLBCL based on serum LDH may guide clinical decision-making for DE-DLBCL patients.

Abstract

Diffuse large B-cell lymphoma (DLBCL) patients with MYC/BCL2 double expression (DE) show poor prognosis and their clinical outcomes after R-CHOP therapy vary immensely. We investigated the prognostic value of DE in aggressive B-cell lymphoma patients (n = 461), including those with DLBCL (n = 417) and high-grade B-cell lymphoma (HGBL; n = 44), in a prospectively immunoprofiled cohort. DE was observed in 27.8% of DLBCLs and 43.2% of HGBLs (p = 0.058). DE-DLBCL patients were older (p = 0.040) and more frequently exhibited elevated serum LDH levels (p = 0.002), higher international prognostic index (IPI; p = 0.042), non-germinal-center B-cell phenotype (p < 0.001), and poor response to therapy (p = 0.042) compared to non-DE-DLBCL patients. In R-CHOP-treated DLBCL patients, DE status predicted poor PFS and OS independently of IPI (p < 0.001 for both). Additionally, in DE-DLBCL patients, older age (>60 years; p = 0.017), involvement of ≥2 extranodal sites (p = 0.021), bone marrow involvement (p = 0.001), high IPI (p = 0.017), CD10 expression (p = 0.006), poor performance status (p = 0.028), and elevated LDH levels (p < 0.001) were significantly associated with poor OS. Notably, DE-DLBCL patients with normal LDH levels exhibited similar PFS and OS to those of patients with non-DE-DLBCL. Our findings suggest that MYC/BCL2 DE predicts poor prognosis in DLBCL. Risk stratification of DE-DLBCL patients based on LDH levels may guide clinical decision-making for DE-DLBCL patients.

Abstract PO-34: Subcutaneous panniculitis-like T-cell lymphoma with HAVCR2 mutation shows unique clinicopathologic features and gene expression profile

Recent studies identified germline HAVCR2 (TIM-3) mutations as the specific genetic predisposition to subcutaneous panniculitis-like T-cell lymphoma (SPTCL). However, distinction between HAVCR2-mutated and HAVCR2-wildtype SPTCLs remains elusive. We studied the prevalence of HAVCR2 mutation in a nation-wide cohort of SPTCL and investigated clinical and molecular distinction between HAVCR2-mutated and HAVCR2-wild-type SPTCLs. A multicenter nationwide cohort of 53 SPTCL cases was established; patients were diagnosed at seven Korean institutions between 2003 and 2020. Histologic features were reviewed by experienced hematopathologists and clinical features were retrospectively reviewed. Whole-exome sequencing (WES) and RNA-seq were performed using formalin-fixed, paraffin-embedded (FFPE) samples of 8 patients diagnosed in Seoul National University Hospital (SNUH), with matched non-neoplastic tissue samples from two patients. Direct sequencing of HAVCR2 exon 2 was successfully carried out using FFPE samples from 33 of the remaining 45 patients. Among 41 patients with available HAVCR2 mutation status, 28 (68.3%) were women, and the median age at diagnosis was 30 years (range 11–74). Ten patients (10/40; 25.0%) suffered hemophagocytic syndrome (HPS) or HPS-like systemic illness during the clinical course, and 14 patients (14/40; 35.0%) progressed during the follow-up. Six patients (6/41; 14.6%) died of disease progression or HPS. We found 18 patients (18/41; 43.9%) with HAVCR2 mutation; 15 patients harbored biallelic HAVCR2 Y82C mutation and 3 patients were noted for heterozygous HAVCR2 Y82C mutation. HAVCR2-mutated SPTCLs occurred in younger patients (median age 26.5 versus 37; Mann-Whitney p-value = 0.003), and were more often complicated by HPS or HPS-like systemic illness (10/18 versus 0/22; Fisher's exact p-value &lt; 0.001), compared to HAVCR2-wild-type SPTCLs. Survival analysis using log-rank test revealed that HAVCR2-mutated SPTCLs had shorter progression-free survival, though statistical significance was not achieved (p-value = 0.081) WES results did not show recurrent genetic alteration other than HAVCR2 Y82C in 4 out of 8 patients. Mutations in genes involved in T/NK cell-associated inflammation (PVRL1, PVRL2, TICAM1, GZMA), epigenetic modification (BAZ2A, KMT2C, KMT2D, SETD1A), JAK-STAT signaling (IFNL2, PIAS3), and NF-kB pathway (PDCD11) were observed in individual cases. Gene set enrichment analyses (GSEA) using RNA-seq results showed significant enrichment of pathways involving TNF-alpha signaling via NF-kB (FDR q-value = 0.008), hypoxia (FDR q-value = 0.009), IL6-JAK-STAT3 signaling (FDR q-value = 0.026), apoptosis (FDR q-value = 0.121), and MTORC1 signaling (FDR q-value = 0.188) in HAVCR2-mutated SPTCLs. HAVCR2 Y82C hotspot mutation frequently occurs in Korean patients with SPTCL, which was characterized by unique clinicopathologic features. SPTCL with HAVCR2 Y82C was enriched with distinct cellular pathways, which remains to be further validated.

Citation Format: Jiwon Koh, Insoon Jang, Seungchan Mun, Cheol Lee, Hee-Jung Cha, Young Ha Oh, Jin Man Kim, Young Hyeh Ko, Jae Ho Han, Heounjeong Go, Jooryung Huh, Kwangsoo Kim, Yoon Kyung Jeon. Subcutaneous panniculitis-like T-cell lymphoma with HAVCR2 mutation shows unique clinicopathologic features and gene expression profile [abstract]. In: Proceedings of the AACR Virtual Meeting: Advances in Malignant Lymphoma; 2020 Aug 17-19. Philadelphia (PA): AACR; Blood Cancer Discov 2020;1(3_Suppl):Abstract nr PO-34.

Comprehensive genetic features of gastric mixed adenoneuroendocrine carcinomas and pure neuroendocrine carcinomas

We aimed to determine the pathogenesis of gastric mixed adenoneuroendocrine carcinoma (MANEC) and pure neuroendocrine carcinoma (NEC), which is largely unknown. Targeted DNA sequencing was performed on 34 tumor samples from 21 patients - 13 adenocarcinoma (ADC)/NEC components from MANECs and eight pure NECs - and 21 matched non-neoplastic gastric tissues. Mutational profiles of MANECs/NECs were compared with those of other tumors using public databases. The majority (64.1%; 59/92) of mutations in MANEC were shared by both ADC and NEC components. TP53 was the most commonly mutated gene in MANEC (69.2%, 9/13) and pure NEC (87.5%, 8/9). All TP53 mutations in MANEC were pathogenic mutations and were shared by both ADC and NEC components. A subset of TP53^WT MANECs had a microsatellite-unstable phenotype or amplifications in various oncogenes including ERBB2 and NMYC, and the only TP53^WT pure NEC harbored MYC amplification. Compared to NEC in other organs, NECs arising from the stomach had unique features including less frequent RB1 mutations. Differentially altered genes of MANEC ADC components were significantly associated with receptor tyrosine kinase signaling pathways, while differentially altered genes of MANEC NEC components were significantly associated with the NOTCH signaling pathway. Our data provide evidence suggesting a possible clonal origin of ADC and NEC components of MANEC, and we found that gastric MANECs and pure NECs are distinct entities with unique mutational profiles and underlying protein networks. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Immunoscore is a strong predictor of survival in the prognosis of stage II/III gastric cancer patients following 5-FU-based adjuvant chemotherapy

The prognostic impact of Immunoscore (IS) in gastric cancer (GC) patients treated with adjuvant chemotherapy remains unelucidated. We evaluated the CD3 + , CD8 + , and Foxp3 + T-lymphocyte densities in tumor centers and invasive margin regions of 389 patients with surgically resected stage II/III GC who received 5-FU-based adjuvant chemotherapy and investigated the impact of IS on survival. In univariate analysis, high CD3 + , CD8 + , and Foxp3 + T-lymphocyte densities in the invasive margin were correlated with better prognosis (all P < 0.05). Patients with high IS had significantly longer disease-free survival (DFS; P < 0.001) and overall survival (OS; P < 0.001). In multivariate analysis, IS demonstrated a powerful prognostic impact on patient outcome [DFS, hazard ratio (HR) = 0.465; 95% confidence interval (CI), 0.306-0.707, P < 0.001; OS, HR = 0.478; 95% CI, 0.308-0.743, P = 0.001]. Additionally, although all EBV-positive cases had high IS, IS was similar in both microsatellite instability (MSI)-high and microsatellite stable (MSS)/MSI-low groups (83.3% and 80.5%, respectively). Subgroup analysis according to MSI status revealed that high IS patients had significant DFS and OS benefits in both MSS/MSI-low (DFS, HR = 0.527, 95% CI, 0.341-0.816, P = 0.004; OS, HR = 0.528, 95% CI, 0.334-0.837, P = 0.007) and MSI-high (DFS, HR = 0.166, 95% CI, 0.033-0.826, P = 0.028; OS, HR = 0.177, 95% CI, 0.036-0.883, P = 0.035) groups. Thus, the assessment of immune cell infiltration based on IS may provide a strong indicator of survival in stage II/III GC patients with curative resection following 5-FU-based adjuvant chemotherapy.

Prediction of TP53 mutations by p53 immunohistochemistry and their prognostic significance in gastric cancer

Background

Recently, molecular classifications of gastric cancer (GC) have been proposed that include TP53 mutations and their functional activity. We aimed to demonstrate the correlation between p53 immunohistochemistry (IHC) and TP53 mutations as well as their clinicopathological significance in GC.

Methods

Deep targeted sequencing was performed using surgical or biopsy specimens from 120 patients with GC. IHC for p53 was performed and interpreted as strong, weak, or negative expression. In 18 cases (15.0%) with discrepant TP53 mutation and p53 IHC results, p53 IHC was repeated.

Results

Strong expression of p53 was associated with TP53 missense mutations, negative expression with other types of mutations, and weak expression with wild-type TP53 (p<.001). The sensitivity for each category was 90.9%, 79.0%, and 80.9%, and the specificity was 95.4%, 88.1%, and 92.3%, respectively. The TNM stage at initial diagnosis exhibited a significant correlation with both TP53 mutation type (p=.004) and p53 expression status (p=.029). The Kaplan-Meier survival analysis for 109 stage II and III GC cases showed that patients with TP53 missense mutations had worse overall survival than those in the wild-type and other mutation groups (p=.028). Strong expression of p53 was also associated with worse overall survival in comparison to negative and weak expression (p=.035).

Conclusions

Results of IHC of the p53 protein may be used as a simple surrogate marker of TP53 mutations. However, negative expression of p53 and other types of mutations of TP53 should be carefully interpreted because of its lower sensitivity and different prognostic implications.

Discovery of Novel Recurrent Mutations and Clinically Meaningful Subgroups in Nodal Marginal Zone Lymphoma

Nodal marginal zone lymphoma (NMZL) is a rare B-cell neoplasm, the genetic and transcriptomic landscape of which are unclear. Using high-throughput sequencing for whole-exome and transcriptome, we investigated the genetic characteristics of NMZL in a discovery cohort (n = 8) and validated their features in an extended cohort (n = 30). Novel mutations in NFKBIE and ITPR2 were found in 7.9% (3/38) and 13.9% (5/36), respectively, suggesting roles for the NF-κB pathway and B-cell-receptor-mediated calcium signaling pathway in the pathogenesis of NMZL. RNA-seq showed that NMZLs were characterized by an aberrant marginal zone differentiation, associated with an altered IRF4-NOTCH2 axis and the enrichment of various oncogenic pathways. Based on gene expression profile, two subgroups were identified. Compared with subgroup 1, subgroup 2 showed the following: the significant enrichment of cell cycle-associated and MYC-signaling pathways, a more diverse repertoire of upstream regulators, and higher Ki-67 proliferation indices. We designated two subgroups according to Ki-67 labeling, and subgroup 2 was significantly associated with a shorter progression-free survival (p = 0.014), a greater proportion of large cells (p = 0.009), and higher MYC expression (p = 0.026). We suggest that NMZL has unique features and, in this study, we provide information as to the heterogeneity of this enigmatic entity.

Clinicopathological features of programmed cell death-1 and programmed cell death-ligand-1 expression in the tumor cells and tumor microenvironment of angioimmunoblastic T cell lymphoma and peripheral T cell lymphoma not otherwise specified

The expression patterns of programmed cell death-1 (PD-1) and programmed cell death-ligand-1 (PD-L1) and their clinicopathological implications were investigated in peripheral T cell lymphoma (PTCL) including angioimmunoblastic T cell lymphoma (AITL) and PTCL-not otherwise specified (PTCL-NOS). PTCL-NOS was further classified into nodal PTCL with follicular helper T cell (Tfh) phenotype ("PTCL-Tfh_new") and "PTCL-NOS_new". PD-1 and PD-L1 expression on tumor cells and reactive immune cells was evaluated using immunohistochemistry. PD-1 and PD-L1 expression on tumor cells (PD-1^T and PD-L1^T, respectively) was interpreted as positive when more than 5% of tumor cells expressed PD-1 or PD-L1. For PD-1 and PD-L1 on tumor cells and/or reactive immune cells (PD-1^T + IC and PD-L1^T + IC, respectively), a cutoff of 10% of cells was used. PD-1^T, PD-L1^T, and PD-L1^T + IC expressions tended to be higher in AITLs than in PTCLs-NOS. PD-1^T, PD-1^T + IC, PD-L1^T, and PD-L1^T + IC expressions tended to be higher in PTCLs with Tfh phenotype including AITLs and "PTCL-Tfh_new" than in PTCLs without Tfh phenotype. The serum LDH level was significantly elevated in patients with PTCL positive for PD-L1^T (P = 0.006) and PD-L1^T + IC (P < 0.001). Patients with PTCL who were positive for combined expression of PD-1^T/PD-L1^T + IC presented at older ages (P = 0.010), nodal diseases (P = 0.001), higher IPI (P = 0.060), and elevated LDH (P = 0.030). Combined PD-1^T/PD-L1^T + IC positivity was related to shorter overall survival in patients with AITL (P = 0.051). Combined PD-1^T/PD-L1^T + IC positivity was a significant poor prognostic factor in patients with stage IV AITL, independent of B symptoms and performance status (HR = 6.282 [CI, 1.655-23.844], P = 0.007). In summary, the PD-1/PD-L1 pathway could be a potential prognostic and therapeutic biomarker for PTCL.

A case of MOG encephalomyelitis with T- cell lymphoma

BACKGROUND

Myelin oligodendrocyte glycoprotein immunoglobulin-G (IgG)-associated encephalomyelitis (MOG-EM) is a distinct inflammatory demyelinating disease. We present an unusual MOG-EM cases with concomitant T-cell lymphoma.

CASE REPORT

A 38-year-old Caucasian male presented with bilateral optic neuritis and multifocal transverse myelitis. He tested positive for MOG-IgG1 and his neurologic symptoms improved with high dose steroid treatment. Six months after his first MOG-EM symptoms, he developed ulcerative skin lesions on his leg and was diagnosed with primary cutaneous γδ T-cell lymphoma. The immunohistochemistry study, performed on his cancer tissue, was negative for MOG.

CONCLUSION

Diagnosis of MOG-EM can be considered in patients with concomitant hematologic malignancy, which might be associated with the dysregulated adaptive immunity rather than the direct presentation of the onconeural antigen by cancer. Further studies need to be conducted for the risks and incidence of malignancy in a larger cohort of MOG-EM.

Morphologic variant of follicular lymphoma reminiscent of hyaline-vascular Castleman disease

Follicular lymphoma (FL) with hyaline-vascular Castleman disease (FL-HVCD)-like features is a rare morphologic variant, with fewer than 20 cases in the literature. Herein, we report a case of FL-HVCD in a 37-year-old female who presented with isolated neck lymph node enlargement. The excised lymph node showed features reminiscent of HVCD, including regressed germinal centers (GCs) surrounded by onion skin-like mantle zones, lollipop lesions composed of hyalinized blood vessels penetrating into regressed GCs, and hyalinized interfollicular stroma. In addition, focal areas of abnormally conglomerated GCs composed of homogeneous, small centrocytes with strong BCL2, CD10, and BCL6 expression were observed, indicating partial involvement of the FL. Several other lymphoid follicles showed features of in situ follicular neoplasia. Based on the observations, a diagnosis of FL-HVCD was made. Although FLHVCD is very rare, the possibility of this variant should be considered in cases resembling CD. Identification of abnormal, neoplastic follicles and ancillary immunostaining are helpful for proper diagnosis.

PD-L1 Testing in Gastric Cancer by the Combined Positive Score of the 22C3 PharmDx and SP263 Assay with Clinically Relevant Cut-offs

Purpose

We provide a comparison between 22C3 pharmDx and SP263 assay, for evaluating programmed death ligand 1 (PD-L1) expression in advanced gastric cancer (GC) patients.

Materials and Methods

The PD-L1 immunohistochemistry by 22C3 pharmDx and SP263 assays was performed in the center of the tumor (CT) and invasive margin (IM) in 379 GC tissues using tissue microarrays and interpreted as combined positive score (CPS) and tumor proportion score (TPS). Of the total samples, 55 samples were independently reviewed by five pathologists.

Results

The two assays showed a high correlation in both the CPS and TPS. At a CPS ≥ 1 cut-off, 219 (57.8%) and 231 (60.9%) GCs were positive for PD-L1 with the 22C3 and SP263 assays, and at ≥ 10 cut-off, 37 (9.8%) and 36 (9.5%) GCs were positive, respectively. The overall percent agreement (OPA) was greater than 90% with CPS ≥ 1 and ≥ 10 cut-offs, and TPS ≥ 1% and ≥ 10% cut-offs. There was higher OPA between the two assays with a CPS cut-off ≥ 10 (99.2%) than ≥ 1 (94.7%). The percent agreement between the CT and IM was higher with a CPS cut-off ≥ 10 (92.9%) than ≥ 1 (77.6%). Patient with positive expression at CPS ≥ 5 cut-off had a significantly better outcomes in both assays. Interobserver variability among five pathologists was higher than the assay variability.

Conclusion

Two assays for PD-L1 expression in GC showed high agreement. These results provide guidance for selecting eligible patients with GC for pembrolizumab treatment.

High-Throughput Multiplex Immunohistochemical Imaging of the Tumor and Its Microenvironment

PURPOSE

The aim of this study was to develop a formalin-fixed paraffin-embedded (FFPE) tissue based multiplex immunochemistry (mIHC) method for high-throughput comprehensive tissue imaging and demonstrate its feasibility, validity, and usefulness.

MATERIALS AND METHODS

The mIHC protocol was developed and tested on tissue microarray slides made from archived gastric cancer (GC) tissue samples. On a single FFPE slide, cyclic immunochemistry for multiple markers of immune cells and cytokeratin for tumor cells was performed; hematoxylin staining was used for demarcation of nuclei. Whole slides were digitally scanned after each cycle. For interpretation of mIHC results, we performed computer-assisted image analysis using publicly available software.

RESULTS

Using mIHC, we were able to characterize the tumor microenvironment (TME) of GCs with accurate visualization of various immune cells harboring complex immunophenotypes. Spatial information regarding intratumoral and peritumoral TME could be demonstrated by digital segmentation of image guided by cytokeratin staining results. We further extended the application of mIHC by showing that subcellular localization of molecules can be achieved by image analysis of mIHC results.

CONCLUSION

We developed a robust method for high-throughput multiplex imaging of FFPE tissue slides. The feasibility and adaptability of mIHC suggest that it is an efficient method for in situ single-cell characterization and analysis.