Establishment and characterization of multiple patient-derived organoids from a case of advanced endometrial cancer

Patient-derived organoids (PDOs) retain the original tumor's characteristics to a large degree and allow direct evaluation of the drug sensitivity, thereby emerging as a valuable resource for both basic and preclinical researches. Whereas most past studies stereotypically adopted a single PDO as an avatar of the patient, it remains to be investigated whether this assumption can be justified even for the tumor with spatial diversity. To address this issue, we established and characterized multiple PDOs originating from various sites of a patient with advanced uterine carcinosarcoma (UCS). Specifically, cancer cells were separately sampled from three sites; resected UCS tumor tissue, the peritoneal lavage fluid, and an intra-uterine brushing of the tumor. The three derived PDOs were morphologically undistinguishable, displaying typical carcinoma organoids-like appearance, but two of them proliferated at a faster rate. The primary tumor harbored mutations in TP53 and STK11 along with amplifications in CCNE1, ERBB2, and KRAS. These two mutations and the CCNE1 amplification were detected in all PDOs, while either KRAS or ERBB2 amplification was selectively observed in each PDO in a mutually exclusive manner. Observed intra-tumor heterogeneity in HER2 expression was differentially reproduced in the PDOs, which mirrored each PDO's sensitivity to HER2 inhibitors. Inter-PDO heterogeneity was also evident in sensitivity to standard cytotoxic agents. Lastly, a drug screening identified four candidate reagents commonly effective to all PDOs. Collectively, we showed that multiple PDOs could help reproduce the spatial diversity of a tumor and serve as a valuable resource in UCS research in many respects.

The diagnostic utility of cytology specimen in a case of EWSR1::NFATC2 sarcoma

EWSR1::NFATC2 sarcoma, a rare round cell sarcoma constituting the majority of EWSR1::non-ETS sarcomas, has recently been defined in the latest WHO classification. To date, the cytological findings of EWSR1::NFATC2 sarcoma remain undocumented. We present the case of a 25-year-old man with a history of polyostotic fibrous dysplasia in the right leg, referred to our hospital with left thigh pain. Cytological findings included metachromasia, minimally pleomorphic round cells, and eosinophilic infiltration. There was no precursor fibrous dysplasia and the initial diagnosis was undifferentiated pleomorphic sarcoma. Following histologic review, we successfully performed immunocytochemistry and fluorescence in situ hybridization (FISH) on archival cytology specimens. The tumor cells were positive for NKX2-2, NKX3-1, and PAX7 and showed amplified 5' single signals of EWSR1 gene. Reverse transcriptase-polymerase chain reaction revealed an in-frame fusion of EWSR1 and NFATC2. This report describes the cytological features of EWSR1::NFATC2 sarcoma and highlights the diagnostic utility of archival cytology specimens.

Multidisciplinary management for primary uterine osteosarcoma, including gene panel testing: case report and literature review

Primary osteosarcoma of the uterus (uOS) is rare, and its standard treatment has not yet been established. Herein, we present the case of a 50-year-old woman with uOS who demonstrated an improved prognosis after multiple surgeries to the metastatic sites. After the initial diagnosis of uOS, the patient showed recurrence and distant metastasis and hence expected to exhibit a poor prognosis. The patient underwent multiple surgical resections of the metastatic as well as primary tumors, which enabled the patient to survive for 24 months after the initial surgery. Considering that the median survival time of patients with uOS is approximately 6 months, the survival rate of our patient is noteworthy. Based on our observations, it is suggested that the resection of the primary and metastatic tumors might contribute to the extension of the survival period of the patient with chemo-resistant uOS.

Immunologic Significance of CD80/CD86 or Major Histocompatibility Complex-II Expression in Thymic Epithelial Tumors

Introduction

Unresectable or recurrent thymic epithelial tumors (TETs) have a poor prognosis, and treatment options are limited. This study aimed to investigate the immunologic significance of CD80/CD86 or major histocompatibility complex class II (MHC-II) expression in TETs, as potential predictive biomarkers for immune checkpoint inhibitors (ICIs).

Methods

We analyzed CD80, CD86, MHC class I (MHC-I), and MHC-II expression in TETs using immunohistochemistry and investigated their association with T-cell infiltration or ICI efficacy. In addition, we generated CD80- or MHC-II-expressing mouse tumors, evaluated the effects of ICIs, and analyzed tumor-infiltrating lymphocytes. We also performed tumor-rechallenge experiments in vivo.

Results

We found that approximately 50% and 30% of TETs had high expression of CD80/CD86 and MHC-II in tumor cells, respectively, and that this expression was related to T-cell infiltration in clinical samples. In mouse models, both CD80 and MHC-II increase the effects of ICIs. In addition, senescent T cells and long-lived memory precursor effector T cells were significantly decreased and increased, respectively, in tumor-infiltrating lymphocytes from CD80-expressing tumors, and rechallenged tumors were completely rejected after the initial eradication of CD80-expressing tumors by programmed cell death protein 1 blockade. Indeed, patients with CD80-high thymic carcinoma had longer progression-free survival with anti-programmed cell death protein 1 monoclonal antibody.

Conclusions

Half of the TETs had high expression of CD80/CD86 or MHC-II with high T-cell infiltration. These molecules could potentially increase the effects of ICIs, particularly inducing a durable response. CD80/CD86 and MHC-II can be predictive biomarkers of ICIs in TETs, promoting the development of drugs for such TETs.

Derivation of pancreatic acinar cell carcinoma cell line HS-1 as a patient-derived tumor organoid

Acinar cell carcinoma (ACC) of the pancreas is a malignant tumor of the exocrine cell lineage with a poor prognosis. Due to its rare incidence and technical difficulties, few authentic human cell lines are currently available, hampering detailed investigations of ACC. Therefore, we applied the organoid culture technique to various types of specimens, such as bile, biopsy, and resected tumor, obtained from a single ACC patient. Despite the initial propagation, none of these organoids achieved long-term proliferation or tolerated cryopreservation, confirming the challenging nature of establishing ACC cell lines. Nevertheless, the biopsy-derived early passage organoid developed subcutaneous tumors in immunodeficient mice. The xenograft tumor histologically resembled the original tumor and gave rise to infinitely propagating organoids with solid features and high levels of trypsin secretion. Moreover, the organoid stained positive for carboxylic ester hydrolase, a specific ACC marker, but negative for the duct cell marker CD133 and the endocrine lineage marker synaptophysin. Hence, we concluded the derivation of a novel ACC cell line of the pure exocrine lineage, designated HS-1. Genomic analysis revealed extensive copy number alterations and mutations in EP400 in the original tumor, which were enriched in primary organoids. HS-1 displayed homozygous deletion of CDKN2A, which might underlie xenograft formation from organoids. Although resistant to standard cytotoxic agents, the cell line was highly sensitive to the proteasome inhibitor bortezomib, as revealed by an in vitro drug screen and in vivo validation. In summary, we document a novel ACC cell line, which could be useful for ACC studies in the future.

Clinical impact of fine needle aspiration cytology on sentinel node biopsy after preoperative chemotherapy for core needle biopsy-proven metastatic lymph nodes

INTRODUCTION

Sentinel node biopsy (SNB) has been increasingly performed for patients with lymph node (LN)-positive (cN1) breast cancer that converted to LN-negative (ycN0) status after neoadjuvant chemotherapy (NAC). This study aimed to clarify the SNB avoidance rates using fine needle aspiration cytology (FNAC) for mLNs after NAC.

METHODS

This study included 68 patients with cN1 breast cancer undergoing NAC from April 2019 to August 2021. Patients with biopsy-proven metastatic clip-marked LNs (clipped LNs) underwent eight cycles of NAC. Ultrasonography (US) was performed to evaluate the effect of the treatment on the clipped LNs, and FNAC was performed after NAC. Patients with ycN0 status determined using FNAC underwent SNB. Those with positive results for FNAC or SNB underwent axillary LNs dissection. Histopathology results and FNA were compared for clipped LNs after NAC.

RESULTS

Of the 68 cases, 53 were ycN0 and 15 were clinically positive LNs after NAC( ycN1) on US. Further, 13% (7/53) of all ycN0 and 60% (9/15) of all ycN1 cases showed residual metastasis in the LNs on FNAC.

CONCLUSION

FNAC was diagnostically useful for patients with ycN0 status on US imaging. Using FNAC for LNs after NAC helped to avoid unnecessary SNB in 13% of the cases.

Transcriptomic analysis reveals high ITGB1 expression as a predictor for poor prognosis of pancreatic cancer

Transcriptomic analysis of cancer samples helps identify the mechanism and molecular markers of cancer. However, transcriptomic analyses of pancreatic cancer from the Japanese population are lacking. Hence, in this study, we performed RNA sequencing of fresh and frozen pancreatic cancer tissues from 12 Japanese patients to identify genes critical for the clinical pathology of pancreatic cancer among the Japanese population. Additionally, we performed immunostaining of 107 pancreatic cancer samples to verify the results of RNA sequencing. Bioinformatics analysis of RNA sequencing data identified ITGB1 (Integrin beta 1) as an important gene for pancreatic cancer metastasis, progression, and prognosis. ITGB1 expression was verified using immunostaining. The results of RNA sequencing and immunostaining showed a significant correlation (r = 0.552, p = 0.118) in ITGB1 expression. Moreover, the ITGB1 high-expression group was associated with a significantly worse prognosis (p = 0.035) and recurrence rate (p = 0.028). We believe that ITGB1 may be used as a drug target for pancreatic cancer in the future.

Machine learning with imaging features to predict the expression of ITGAV, which is a poor prognostic factor derived from transcriptome analysis in pancreatic cancer

Radiogenomics has attracted attention for predicting the molecular biological characteristics of tumors from clinical images, which are originally a collection of numerical values, such as computed tomography (CT) scans. A prediction model using genetic information is constructed using thousands of image features extracted and calculated from these numerical values. In the present study, RNA sequencing of pancreatic ductal adenocarcinoma (PDAC) tissues from 12 patients was performed to identify genes useful in evaluating clinical pathology, and 107 PDAC samples were immunostained to verify the obtained findings. In addition, radiogenomics analysis of gene expression was performed by machine learning using CT images and constructed prediction models. Bioinformatics analysis of RNA sequencing data identified integrin αV (ITGAV) as being important for clinicopathological factors, such as metastasis and prognosis, and the results of sequencing and immunostaining demonstrated a significant correlation (r=0.625, P=0.039). Notably, the ITGAV high‑expression group was associated with a significantly worse prognosis (P=0.005) and recurrence rate (P=0.003) compared with the low‑expression group. The ITGAV prediction model showed some detectability (AUC=0.697), and the predicted ITGAV high‑expression group was also associated with a worse prognosis (P=0.048). In conclusion, radiogenomics predicted the expression of ITGAV in pancreatic cancer, as well as the prognosis.

Treatment Strategy for Patients with HR-Positive HER2-Negative Metastatic Breast Cancer That Progressed on CDK4/6 Inhibitors

Background/Aims

The study aim was to evaluate if mTOR inhibitors can be considered as a treatment option for HR+ HER2- metastatic breast cancer (MBC) after progression on CDK4/6 inhibitors in clinical practice.

Methods

We retrospectively collected the clinicopathological data of patients with HR+ HER2- MBC treated with CDK4/6 inhibitors and subsequent therapies at our institution between 2014 and 2020. The patients were divided into 3 groups according to the type of subsequent treatment: (A) exemestane plus everolimus, (B) endocrine monotherapy, and (C) chemotherapy. Overall survival (OS) was estimated by using the Kaplan-Meier method and compared by using the log-rank test. The efficacy and adverse events (AEs) of each subsequent treatment were assessed by using Fisher's exact tests.

Results

Eighty-six patients (34 in group A, 20 in group B, 32 in group C) were included. The most common endocrine therapy in group B was fulvestrant (40%). The major chemotherapy regimen in group C was eribulin (25%). The median OS times after stopping CDK4/6 inhibitors were 34.5 months (95% confidence interval, 17.2 to NA), 13.6 months (3.9 to NA), and 19.5 months (18.8 to NA) in group A, group B, and group C, respectively. The only significant difference in OS was observed between group A and group B (20.9 months; p = 0.003). There was no difference in the incidence of grade 3 AEs between groups A and C or in the frequency of treatment discontinuation because of AEs among the 3 groups.

Conclusion

Our study shows that mTOR inhibitors might be an effective treatment option for patients with HR+ HER2- MBC previously treated with CDK4/6 inhibitors.

Synchronous early-stage breast cancer and axillary follicular lymphoma diagnosed by core needle biopsy: A case report

Synchronous double cancers are an infrequent finding. The focus of this study was a case of diagnosed synchronous double breast cancer (BC) and axillary (Ax) follicular lymphoma (FL). The patient was a 73-year-old woman who had been visiting her local doctor for follow-up of a fibroadenoma of the left breast, and was referred to our hospital after being diagnosed with invasive ductal carcinoma (IDC) of the left breast. Ultrasonography (US) revealed enlarged Ax lymph nodes (LNs) and US-guided core needle biopsy (CNB) was performed. CNB revealed no metastasis of IDC; however, a diagnosis of FL was made. Therefore, the patient was diagnosed with synchronous double BC and Ax FL and underwent partial surgical resection of the BC and close monitoring of the FL. To the best of our knowledge, this is the first case of malignant lymphoma diagnosed by CNB of Ax LNs during preoperative BC screening. CNB allows for a shorter waiting time for the examination, and it is considered to be minimally invasive, cost-effective and non-inferior to surgical resection in terms of specimen volume. Therefore, active preoperative evaluation of Ax LNs using US-guided CNB may contribute to BC staging, and may also help diagnose synchronous cancers.

Prediction of the differences in tumor mutation burden between primary and metastatic lesions by radiogenomics

Tumor mutational burden (TMB) is gaining attention as a biomarker for responses to immune checkpoint inhibitors in cancer patients. In this study, we evaluated the status of TMB in primary and liver metastatic lesions in patients with colorectal cancer (CRC). In addition, the status of TMB in primary and liver metastatic lesions was inferred by radiogenomics on the basis of computed tomography (CT) images. The study population included 24 CRC patients with liver metastases. DNA was extracted from primary and liver metastatic lesions obtained from the patients and TMB values were evaluated by next‐generation sequencing. The TMB value was considered high when it equaled to or exceeded 10/100 Mb. Radiogenomic analysis of TMB was performed by machine learning using CT images and the construction of prediction models. In 7 out of 24 patients (29.2%), the TMB status differed between the primary and liver metastatic lesions. Radiogenomic analysis was performed to predict whether TMB status was high or low. The maximum values for the area under the receiver operating characteristic curve were 0.732 and 0.812 for primary CRC and CRC with liver metastasis, respectively. The sensitivity, specificity, and accuracy of the constructed models for TMB status discordance were 0.857, 0.600, and 0.682, respectively. Our results suggested that accurate inference of the TMB status is possible using radiogenomics. Therefore, radiogenomics could facilitate the diagnosis, treatment, and prognosis of patients with CRC in the clinical setting.

Genetic subtype classification using a simplified algorithm and mutational characteristics of diffuse large B-cell lymphoma in a Japanese cohort

Recent large-scale genetic studies have proposed a new genetic classification of diffuse large B-cell lymphoma (DLBCL), which is clinically and biologically heterogeneous. However, the classification methods were complicated to be introduced into clinical practice. Here we retrospectively evaluated the mutational status and copy number changes of 144 genes in 177 Japanese patients with DLBCL, using targeted DNA sequencing. We developed a simplified algorithm for classifying four genetic subtypes-MYD88, NOTCH2, BCL2, and SGK1-by assessing alterations in 18 representative genes and BCL2 and BCL6 rearrangement status, integrating the significant genes from previous studies. In our cohort and another validation cohort from published data, the classification results in our algorithm showed close agreement with the other established algorithm. A differential prognosis among the four groups was observed. The NOTCH2 group showed a particularly poorer outcome than similar groups in previous reports. Furthermore, our study revealed unreported genetic features in the DLBCL subtypes that are mainly reported in Japanese patients, such as CD5-positive DLBCL and methotrexate-associated lymphoproliferative disorders. These results indicate the utility of our simplified method for DLBCL genetic subtype classification, which can facilitate the optimisation of treatment strategies. In addition, our study highlights the genetic features of Japanese patients with DLBCL.

Surgical resection of undifferentiated pleomorphic sarcoma (UPS) with jejunal perforation, a suspected case of metastasis of lung cancer

Undifferentiated pleomorphic sarcoma (UPS) in the gastrointestinal tract is rare. According to the diagnostic criteria after the World Health Organization 2013 reclassification, there has been only one case of UPS with perforation of the gastrointestinal tract. A 71-year-old man who was undergoing outpatient chemotherapy at the department of respiratory medicine of our hospital for lung cancer and brain metastasis, was admitted to our hospital with sudden high fever and abdominal pain. A computed tomography scan showed free air in the abdominal cavity with thickening of part of the jejunal wall. We suspected jejunal metastasis of lung cancer and performed emergency surgery for acute peritonitis due to gastrointestinal perforation in the same area. A Bormann type 2 tumour was found in the jejunum with perforation. The histopathological diagnosis was UPS. Ten months have passed since the surgery, and there has been no recurrence of UPS and no significant change in lung cancer. Primary UPS of the gastrointestinal tract is rare, and cases with perforation are extremely rare. Currently, ten months have passed since the surgery, and no recurrence has been observed. We encountered a case of UPS in which it was difficult to distinguish metastasis from lung cancer to the jejunum, and the emergency surgery gave us the chance to confirm the definitive diagnosis and save the patient's life.

CA19-9-producing esophageal adenocarcinoma originating from the esophageal cardia of the mid-thoracic esophagus: a case report

BACKGROUND

Although there are many studies on primary esophageal adenocarcinoma arising from Barrett's esophagus or ectopic gastric mucosa, reports on adenocarcinoma arising from esophageal cardiac glands are extremely rare. Herein, we report a case of mid-thoracic cancer antigen 19-9 (CA 19-9)-producing primary esophageal adenocarcinoma, which presumably originated from the cardiac glands.

CASE PRESENTATION

A 74-year-old man was referred to our department with advanced esophageal cancer, which initially presented with dyspepsia. Serum levels of cancer antigen 19-9 (CA 19-9) were elevated (724.89 U/ml). Upper gastrointestinal endoscopy revealed a type 2 tumor on the posterior wall of the mid-thoracic esophagus approximately 29-32 cm from the incisor. Mucosal biopsy was consistent with a diagnosis of adenocarcinoma. Contrast-enhanced computed tomography showed a circumferential wall thickening in the mid-thoracic esophagus without enlarged lymph nodes or distant metastasis. Positron emission tomography-computed tomography showed accumulation in the primary tumor, but no evidence of lymph node or distant metastasis. According to these findings, the adenocarcinoma was staged as cT3N0M0, thereby, requiring subtotal esophagectomy with lymph node dissection. Postoperative course was uneventful. Histopathologic analysis revealed a 50 × 40 mm moderately differentiated adenocarcinoma with invasion to the thoracic duct and lymph node metastasis at #108(1/4), #109R(1/3), and #109L(1/3). After surgery, the stage was revised to moderately differentiated pT4apN2pM0 (pStage III). Immunostaining revealed expression of CA19-9 and suggested esophageal cardiac gland origin of the tumor. Three months after the surgery, the patient showed no recurrence and is undergoing outpatient observation.

CONCLUSIONS

We experienced a case of mid-thoracic CA19-9-producing primary esophageal adenocarcinoma, which was presumed to have originated in the esophageal cardiac glands. Due to the scarcity of studies regarding this condition, specific management needs to be further clarified.

Probing the tumorigenic potential of genetic interactions reconstituted in murine fallopian tube organoids

Genetically engineered mice have been the gold standard in modeling tumor development. Recent studies have demonstrated that genetically engineered organoids can develop subcutaneous tumors in immunocompromised mice, at least for organs that prefer predominant driver mutations for tumorigenesis. To further substantiate this concept, the fallopian tube (FT), a major cell of origin of ovarian high-grade serous carcinoma (HGSC), which almost invariably carries TP53 mutations, was investigated for p53 inactivation-driven tumorigenesis. Murine FT organoids subjected to lentiviral Cre-mediated Trp53 deletion did not develop tumors. However, subsequent suppression of Pten and simultaneous induction of mutant Pik3ca led to the development of carcinoma in situ and HGSC-like tumors, respectively, whereas concurrent deletion of Apc resulted in the development of benign cysts, mirroring frequent activation of the PI3K/AKT axis and the marginal impact of Wnt pathway activation in HGSC. Consistent with the frequent activation of the RAS pathway in HGSC, mutant Kras cooperated with Trp53 deletion for the development of tumors, which unexpectedly contained sarcoma cells in addition to carcinoma cells, despite the epithelial origin of the inoculated organoids. This finding is in sharp contrast with the exclusive adenocarcinoma development from gastrointestinal organoids with the same genotype reported in previous studies, suggesting a tissue-specific epithelial-mesenchymal transition program. In tumor-derived organoids, the Cre-mediated recombination rate reached 100% for Trp53 but not for the other genes, highlighting the advantage of p53 inactivation in FT tumorigenesis. The Trp53 wildtype FT organoids expressing the mutant Kras developed sarcoma and carcinoma upon Cdkn2a suppression and Tgfbr2 deletion, respectively, revealing novel pro-tumorigenic genetic cooperation and critical roles of TGF-β signaling for epithelial-mesenchymal transition in FT-derived tumorigenesis. Collectively, the organoid-based approach represents a shortcut to tumorigenesis and provides novel insights into the relationships among genotype, cell type, and tumor phenotype underlying tumorigenesis. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

MCT4 is induced by metastasis-enhancing pathogenic mitochondrial NADH dehydrogenase gene mutations and can be a therapeutic target

Pathogenic mitochondrial NADH dehydrogenase (ND) gene mutations enhance the invasion and metastasis of various cancer cells, and they are associated with metastasis in human non-small cell lung cancer (NSCLC). Moreover, monocarboxylate transporter 4 (MCT4) is overexpressed in solid cancers and plays a role in cancer cell proliferation and survival. Here, we report that MCT4 is exclusively expressed in mouse transmitochondrial cybrids with metastasis-enhancing pathogenic ND6 mutations. A high level of MCT4 is also detected in human NSCLC cell lines and tissues predicted to carry pathogenic ND mutations and is associated with poor prognosis in NSCLC patients. MCT4 expression in the cell lines is suppressed by N-acetyl-L-cysteine. Phosphatidylinositol-3 kinase (PI3K), AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) are involved in the regulation of MCT4 expression in the transmitochondrial cybrid cells. An MCT1/4 inhibitor effectively kills NSCLC cells with predicted pathogenic ND mutations, but an MCT1/2 inhibitor does not have the same effect. Thus, MCT4 expression is augmented by pathogenic ND mutations and could be a biomarker and a therapeutic target in pathogenic ND mutation-harbouring metastatic tumours.

Kras activation in endometrial organoids drives cellular transformation and epithelial-mesenchymal transition

KRAS, an oncogene, is frequently activated by mutations in many cancers. Kras-driven adenocarcinoma development in the lung, pancreas, and biliary tract has been extensively studied using gene targeting in mice. By taking the organoid- and allograft-based genetic approach to these organs, essentially the same results as in vivo models were obtained in terms of tumor development. To verify the applicability of this approach to other organs, we investigated whether the combination of Kras activation and Pten inactivation, which gives rise to endometrial tumors in mice, could transform murine endometrial organoids in the subcutis of immunodeficient mice. We found that in KrasG12D-expressing endometrial organoids, Pten knockdown did not confer tumorigenicity, but Cdkn2a knockdown or Trp53 deletion led to the development of carcinosarcoma (CS), a rare, aggressive tumor comprising both carcinoma and sarcoma. Although they originated from epithelial cells, some CS cells expressed both epithelial and mesenchymal markers. Upon inoculation in immunodeficient mice, tumor-derived round organoids developed carcinoma or CS, whereas spindle-shaped organoids formed monophasic sarcoma only, suggesting an irreversible epithelial-mesenchymal transition during the transformation of endometrial cells and progression. As commonly observed in mutant Kras-driven tumors, the deletion of the wild-type Kras allele was identified in most induced tumors, whereas some epithelial cells in CS-derived organoids were unexpectedly negative for KrasG12D. Collectively, we showed that the oncogenic potential of KrasG12D and the histological features of derived tumors are context-dependent and varies according to the organ type and experimental settings. Our findings provide novel insights into the mechanisms underlying tissue-specific Kras-driven tumorigenesis.

CDK4 overexpression is a predictive biomarker for resistance to conventional chemotherapy in patients with osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor, and its sensitivity to preoperative chemotherapy is a significant prognostic factor. The present study aimed to identify potential genomic markers for the prediction of chemosensitivity in patients with OS using a genomic approach. A total of 50 pediatric and adolescent patients diagnosed with high‑grade OS were selected. Each pre‑therapeutic biopsy sample was subjected to comparative genomic hybridization array analysis and targeted exome sequencing. Although no recurrent gene mutation was observed in chemoresistant tumors, copy number analysis detected recurrent gain of chromosome 12q14.1, which was significantly more frequent (5/21; 24%) in the poor responder cohort than in the good responder cohort (0/29; 0%; P<0.01). Subsequent expression analysis revealed that CDK4 was the only gene in the 12q14.1 gained region with an expression level that was positively associated with copy number gains. In order to elucidate the effect of CDK4 on drug sensitivity, CDK4‑overexpressing OS cell lines were treated with cisplatin (CDDP); significant attenuation of CDDP sensitivity, demonstrated by increased cell viability and decreased expression of cleaved caspase‑9, was induced by enforced expression of CDK4. In addition, treatment with CDK4/6 inhibitor palbociclib in CDK4‑overexpressing U2OS cells facilitated apoptosis and a significant decrease in cell viability in a dose‑dependent manner. In conclusion, the results of the present study showed that higher expression and amplification of CDK4 in tumors is a predictive biomarker for resistance to conventional chemotherapy in patients with OS and that palbociclib is a promising drug for this therapeutically challenging cohort.

A case of cervical clear cell carcinoma with serous component

Cervical clear cell carcinoma (CCCC) is rare. This report describes the case of CCCC with a serous component. A 22-year-old woman presented with vaginal bleeding. A cervical tumor was discovered: pelvic magnetic resonance imaging revealed a tumor measuring 46 mm. Radical hysterectomy was performed based on the diagnosis of stage IB2 cervical cancer. After histological examination of the specimen revealed a coexisting invasive clear cell carcinoma (95%) and serous carcinoma (5%), five cycles of nedaplatin and irinotecan therapy were administered as postoperative adjuvant chemotherapy. Local recurrence in the vaginal vault was observed at 7 months after surgery. Radiation therapy and chemotherapy were administered. The patient is alive without evidence of recurrence at 26 months after surgery.

Nuclear grade and comedo necrosis of ductal carcinoma in situ as histopathological eligible criteria for the Japan Clinical Oncology Group 1505 trial: an interobserver agreement study

OBJECTIVE

The Japan Clinical Oncology Group 1505 trial is a single-arm multicentre prospective study that examined the possibility of non-surgical follow-up with endocrine therapy for patients with low-grade ductal carcinoma in situ. In that study, the eligible criteria included histopathological findings comprising low to intermediate nuclear grade and absence of comedo necrosis, and cases were entered according to the local histopathological diagnosis. Nuclear grade is largely based on the Consensus Conference criteria (1997), whereas comedo necrosis is judged according to the Rosen's criteria (2017). The purpose of this study was to standardize and examine the interobserver agreement levels of these histopathological criteria amongst the participating pathologists.

METHODS

We held slide conferences, where photomicrographs of haematoxylin-eosin-stained slides from 68 patients with ductal carcinoma in situ were presented using PowerPoint. The nuclear grade and comedo necrosis statuses individually judged by the pathologists were analysed using κ statistics.

RESULTS

In the first and second sessions, where 22 cases each were presented, the interobserver agreement levels of nuclear grade whether low/intermediate grade or high grade were moderate amongst 29 and 24 participating pathologists, respectively (κ = 0.595 and 0.519, respectively). In the third session where 24 cases were presented, interobserver agreement levels of comedo necrosis or non-comedo necrosis were substantial amongst 25 participating pathologists (κ = 0.753).

CONCLUSION

Although the concordance rates in nuclear grade or comedo necrosis were not high in a few of the cases, we believe that these results could provide a rationale for employing the present criteria of nuclear grade and comedo necrosis in the clinical study of ductal carcinoma in situ.

Clinical impact of the biology of synchronous axillary lymph node metastases in primary breast cancer on preoperative treatment strategy

BACKGROUND AND OBJECTIVES

The purpose of this study was to assess the utility of determining the biological features of synchronous axillary lymph node (syLN) metastasis of breast cancer in evaluating the efficacy of preoperative systemic chemotherapy (PST).

MATERIALS AND METHODS

The retrospective subjects initially comprised 59 patients (T1c-4 N1-3 M0) diagnosed with syLN metastasis via core needle biopsy who received PST. The hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status in each patient was assessed in primary breast tumor (pBT) and syLNs using immunohistochemistry, and the patients were classified into HR(+), HER2(+), and triple negative breast cancer (TN) subtypes.

RESULTS

Subtype shift (SS) of pBT in syLNs was observed in 28% cases for HR(+), in 6% cases for the HER2(+), and in 16% cases for the TN. The pCR rate of the pBT and syLNs types were 45% and 36% in the HR(+), 45% and 39% in the TN, and 94% and 100% in the HER2(+), respectively. In SS cases, the pCR rate was significantly higher in 75% cases compared with 33% of the no-SS cases.

CONCLUSION

A SS in syLNs was more frequent in HR(+) than in other types.

Clinical value of PET/CT with carbon-11 4DST in the evaluation of malignant and benign lung tumors

OBJECTIVES

The aim of this study was to assess the clinical value of [¹¹C]4DST uptake in patients with lung nodules, including benign and malignant tumors, and to assess the correlation between [¹¹C]4DST uptake and proliferative activity of tumors in comparison with [¹⁸F]FDG uptake.

METHODS

Twenty-six patients (22 males and 4 females, mean age of 65.5-year-old) were analyzed in this prospective study. Patients underwent [¹¹C]4DST and [¹⁸F]FDG PET/CT imaging on the same day. Diagnosis of each lung nodule was confirmed by histopathological examination of tissue specimens at surgery, or during clinical follow-up after the PET/CT studies. To assess the utility of the semi-quantitative evaluation method, the SUV_max was calculated of [¹¹C]4DST and [¹⁸F]FDG uptake by the lesion. Proliferative activities of each tumor as indicated by the immunohistochemical Ki-67 index was also estimated using surgical specimens of patients. Then the relationship between the SUV_max of both PET/CT and the Ki-67 index was examined. Furthermore, the relationship between the uptake of [¹¹C]4DST or [¹⁸F]FDG and the histopathological findings, the clinical stage, and the clinical outcome of patients were also assessed.

RESULTS

There was a positive linear relationship between the SUV_max of [¹¹C]4DST images and the Ki-67 index (Correlation coefficients = 0.68). The SUV_max of [¹¹C]4DST in the 26 lung nodules were 1.65 ± 0.40 for benign lesions, 3.09 ± 0.83 for adenocarcinomas (P < 0.001 between benign and adenocarcinoma), and 2.92 ± 0.58 for SqCCs (P < 0.001 between benign and SqCC). Whereas, the SUVmax of [¹⁸F]FDG were 2.38 ± 2.27 for benign lesions, 6.63 ± 4.24 for adenocarcinomas (n.s.), and 7.52 ± 2.84 for SqCCs (n.s.). The relationship between TNM tumor stage and the SUV_max of [¹¹C]4DST were 2.54 ± 0.37 for T1, 3.48 ± 0.57 for T2, and 4.17 ± 0.72 for T3 (P < 0.005 between T1 and T2, and P < 0.001 between T1 and T3). In comparison with the TNM pathological stage, SUVmax of [¹¹C]4DST were 2.63 ± 0.49 for stage I, 3.36 ± 0.23 for stage II, 3.40 ± 1.12 for stage III, and 4.65 for stage IV (P < 0.05 between stages I and II). In comparison of the clinical outcome, the SUV_max of [¹¹C]4DST were 2.72 ± 0.56 for the no recurrence (No Rec.) group, 3.10 ± 0.33 for the recurrence-free with adjuvant chemotherapy after the surgery (the No Rec. Adjv. CTx. group) and 4.66 ± 0.02 for the recurrence group (Rec. group) (P < 0.001 between the No Rec and Rec. groups, and P < 0.005 between the No Rec. Adjv. CTx. and Rec. groups).

CONCLUSIONS

PET/CT with [¹¹C]4DST is as feasible for imaging of lung tumors as [¹⁸F]FDG PET/CT. For diagnosing lung tumors, [¹¹C]4DST PET is useful in distinguishing benign nodules from malignancies. [¹¹C]4DST uptake in lung carcinomas is correlated with the proliferative activity of tumors, indicating a promising noninvasive PET imaging of DNA synthesis in malignant lung tumors.

Radiogenomics for predicting p53 status, PD-L1 expression, and prognosis with machine learning in pancreatic cancer

BACKGROUND

Radiogenomics is an emerging field that integrates "Radiomics" and "Genomics". In the current study, we aimed to predict the genetic information of pancreatic tumours in a simple, inexpensive, and non-invasive manner, using cancer imaging analysis and radiogenomics. We focused on p53 mutations, which are highly implicated in pancreatic ductal adenocarcinoma (PDAC), and PD-L1, a biomarker for immune checkpoint inhibitor-based therapies.

METHODS

Overall, 107 patients diagnosed with PDAC were retrospectively examined. The relationship between p53 mutations as well as PD-L1 abnormal expression and clinicopathological factors was investigated using immunohistochemistry. Imaging features (IFs) were extracted from CT scans and were used to create prediction models of p53 and PD-L1 status.

RESULTS

We found that p53 and PD-L1 are significant independent prognostic factors (P = 0.008, 0.013, respectively). The area under the curve for p53 and PD-L1 predictive models was 0.795 and 0.683, respectively. Radiogenomics-predicted p53 mutations were significantly associated with poor prognosis (P = 0.015), whereas the predicted abnormal expression of PD-L1 was not significant (P = 0.096).

CONCLUSIONS

Radiogenomics could predict p53 mutations and in turn the prognosis of PDAC patients. Hence, prediction of genetic information using radiogenomic analysis may aid in the development of precision medicine.

Prognostic significance of p16 protein in pancreatic ductal adenocarcinoma

The p16 gene, which is also known as CDKN2A, INK4A, or CDK4I, and its products that are known to be cell cycle inhibitors and tumor suppressors have been reported to be altered in various human tumor types. Altered p16 has been indicated to be correlated with negative p16 expression using immunohistochemistry (IHC). However, its association with the prognosis remains controversial because the findings of previous studies are inconsistent. The current study evaluated the relationship between the expression levels of p16 and the clinicopathological features associated with prognosis in patients with primary pancreatic ductal adenocarcinomas (PDACs). From January 2013 to December 2017, tissues of 103 PDAC patients who had undergone elective pancreatic resection were obtained and assessed for p16 expression by IHC. No correlation was observed between p16 status and clinicopathological factors (P>0.05). Notably, negative p16 expression on IHC was not significantly associated with poor prognosis using the Kaplan-Meier method.

SPDR-09 CHANGES IN CELL CYCLE-RELATED GENE EXPRESSIONS OF GLIOBLASTOMAS BEFORE AND IMMEDIATELY AFTER CHEMO-RADIATION THERAPY

PURPOSE/OBJECTIVE

The molecular responses of glioblastomas (GBMs) to hypofractionated IMRT/TMZ were investigated to elucidate the molecular targets included in the resistance of these tumors to chemo-radiation therapy.

MATERIALS /METHODS

Phase I study of neo-adjuvant IMRT (72Gy/12Fx.)/TMZ for the treatment of patients with GBMs had been performed previously in our institution. In this trial, stereotactic biopsy of the tumor to confirm the pathological diagnosis prior to treatment was required, and tumor removal was scheduled within 10 days after completion of IMRT/TMZ. Therefore, both the tumor samples before and immediately after IMRT/TMZ were available. By comparing the gene expression profiles before and after IMRT/TMZ using the total mRNA sequencing (RNAseq) analysis, molecular responses of GBMs against IMRT/TMZ were investigated. More than two-fold change of expression levels was defined as significant.

RESULTS

Tumor sample sets from five patients with GBMs were investigated. Among the 17,532 genes evaluated, 35 genes were found to show significant changes in gene expression in all cases, and 450 genes in more than half of the cases. Among the DNA repair related genes, DDB2 was the only gene that showed significant up-regulation in all cases. On the other hand, among the cell cycle checkpoint related genes, gene expressions of CKD1/CCNB were decreased in all cases. Although the expression of TP53 was not changed, the expressions of CDKN1A/GADD45/Reprimo/SFN were also reduced. Moreover, although the expression change of CHK1 was not found, the expressions of CDC25/PLK1/AURKA were decreased in more than half of the cases. From these results, it was considered that GBM arrested the cell cycle at the G2/M checkpoint without regulation of TP53 or CHK1 after IMRT/TMZ.

CONCLUSIONS

Our results suggested that cell cycle arrest in G2/M plays a significant role in survival of GBM cells after IMRT/TMZ.

Establishment and characterization of patient-derived organoids from a young patient with cervical clear cell carcinoma

Cervical clear cell carcinoma (cCCC) constitutes an extremely rare subtype of cervical cancer. Consequently, its pathogenesis remains largely unknown, with no cell lines established from primary tumors. Here, we report the first establishment of cCCC organoids, from biopsy samples of a 23‐year‐old patient diagnosed with cCCC. By applying a protocol that we recently optimized for gynecological tumors, we were able to propagate a patient‐derived cell line (PDC) for more than 6 months as organoids. This PDC tolerated cryopreservation and proliferated either as spheroids or adherent cells, and developed xenografts in immunodeficient mice, ensuring robust utility as a cell line. Intriguingly, the resected tumor focally contained serous carcinoma (SC) in a tiny protruding lesion. Both organoids and derivative xenografts resembled the CCC component of the original tumor in histology, immunostaining profile, and genome‐wide copy number changes, including focal gain of MET. Genomic analysis revealed that both organoids and the CCC component harbored only a few mutations, of which 2 mutations were shared in common. In contrast, the SC component showed a mutator‐phenotype and prominent genome instability along with biallelic inactivation of TP53, but none of them were found in organoids or the CCC component. The PDC proved sensitive to major chemotherapeutic agents and MET inhibitors. These observations clearly indicated that the PDC, designated as YMC7, can be used as a novel cCCC cell line and provide novel insights into the pathogenesis of mixed cervical adenocarcinoma. As a valuable resource for rare cancer, it will likely contribute to investigations in many fields.

A case of primary pulmonary leiomyosarcoma completely resected after neoadjuvant chemotherapy

Background

Primary pulmonary leiomyosarcoma is a rare malignant tumor. We herein report a case of primary pulmonary leiomyosarcoma that was completely resected by surgery after neoadjuvant chemotherapy.

Case presentation

A 60-year-old man presented with cough. Chest computed tomography showed an 11-cm mass in the right upper lobe of the lung that had invaded the superior vena cava. Endobronchial ultrasound-guided transbronchial needle aspiration revealed leiomyosarcoma of the lung. We considered complete resection of the tumor to be very difficult because of the tumor invasion into the right atrium inflow of the superior vena cava, so we performed chemotherapy using doxorubicin for five cycles. After chemotherapy, the tumor size decreased to 5.6 cm, and we performed right upper lobectomy with combined resection of the superior vena cava. The tumor was completely resected by surgery. The patient is alive without recurrence 17 months postoperatively.

Conclusions

We encountered a case of primary pulmonary leiomyosarcoma that was successfully treated by surgery after neoadjuvant chemotherapy. Doxorubicin monotherapy was effective in this case. Surgery combined with neoadjuvant chemotherapy should be considered for such cases, as a long-term survival can be achieved by complete resection of primary pulmonary leiomyosarcoma.

Prognostic factors and survival in Japanese patients with brain metastasis from renal cell cancer

BACKGROUND

Patients with brain metastasis from renal cell carcinoma have poor outcomes despite recent advances in diagnosis and treatment. Moreover, factors affecting such poor outcomes are unclear. This study aimed to evaluate the prognostic factors associated with overall survival in renal cell carcinoma patients with brain metastasis.

METHODS

We retrospectively reviewed the data of 50 consecutive patients with brain metastasis from renal cell carcinoma at our institution between 1988 and 2017. The evaluated prognostic factors for overall survival included clinicopathological factors at diagnosis, treatment for brain metastasis, and the Graded Prognostic Assessment score of renal cell carcinoma. The associations between preoperative clinicopathological factors and overall survival were assessed using the log-rank test and Cox proportional hazards models for univariate and multivariate analyses, respectively.

RESULTS

Forty-five patients were included, among whom 39 died during follow-up. The median follow-up was 8.2 months. The median survival time was 8.2 months (95% confidence interval 5.5-13.7). A Graded Prognostic Assessment score ≤ 2 (hazard ratio 1.967; 95% confidence interval 1.024-3.892; P = 0.042), the presence of sarcomatoid components (hazard ratio 3.299; 95% confidence interval 1.424-7.193; P = 0.007), and no treatment for brain metastasis (hazard ratio 2.594; 95% confidence interval 1.033-5.858; P = 0.043) were independently associated with poor prognosis in the multivariate analysis.

CONCLUSIONS

Patients with renal cell carcinoma who develop brain metastasis have poor overall survival. The Graded Prognostic Assessment score, sarcomatoid components, and treatment for brain metastasis from renal cell carcinoma were independent factors associated with prognosis.

Abstract P3-03-22: Prognostic impact of axillary lymph node status after neoadjuvant chemotherapy for patients with breast cancer

BACKGROUND:

Patients were stratified by final pathological axillary status: ypN0, ypN1, pN0 or pN1.

The prognostic impact of lymph node involvement after neoadjuvant chemotherapy (NAC) for breast cancer is not straightforward. The aim of this study was to compare overall survival (OS) between pathologically

node-positive T1,T2 T3 breast cancer patients treated with NAC, with ypN0 or ypN1 and those treated without NAC with pN0 or pN1.

METHODS:

A total of 3903 consecutive patients with operable breast cancer were prospectively identified at our institution between April 2006 and December 2017. Patients with suspicious axillary LN of breast cancer were assessed using preoperative imaging, underwent fine-needle aspiration cytology or core needle biopsy.

The patients in this study were divided into four groups as follows: the ER(+), the ER(+)/HER2(+) , the HER2(+) and the Triple negative (TN) group.

We evaluate the prognostic impact of the ypN0, ypN1 (with one to three positive lymph nodes after NAC), pN0 and pN1 with no NAC.

The main outcome measures DFS and OS were analyzed using Kaplan–Meier survival analysis.

Result

A number of 270 and 3633 patients were included for NAC and non NAC, respectively. Pathologic nodal status was ypN0 in 58%, ypN1 in 42% for NAC and pN0 in 76%, pN1 in 24% of patients for non NAC.

Overall, 10-year DFS and OS was 81%, 93% in ypN0, 67%, 80% in ypN1, in 90%, 97%, in pN0 and 83%, 94% in pN1 (p &lt;0.001).

In subgroup analysis, 10-year DFS of ypN0, ypN1, pN0 and pN1 was 86%,77%,95% and 80% in the ER group, 91%,56%,93%,and 76% in the ER/HER2 group,89%,55%,91% and 80% in the HER2 group, 85%,59%,92% and 80% in the TN group.

10 years DFS for the ER group were significantly different between ypN0 and pN0 (HR, 2.42 (1.03–4.86, p = 0.04) but were not significantly different between ypN0 and pN0 for the ER/HER2 group (HR 3.58 (0.2–6.88, p = 0.66), for the HER2 group (HR 2.6 (0.78–7.65, p = 0.10) and for the TN group (HR 1.22(0.56–2.38, p = 0.58), respectively).

In all group, DFS for ypN1 was inferior to ypN0.

Conclusions

In the ER group treated with NAC, DFS for ypN0 be inferior to pN0 with adjuvant treatment. In the HER2, the ERHER2 and the TN group treated with NAC, ypN0 is similar to pN0 with adjuvant chemotherapy.

Axillary nodal status ypN1 in each subgroup is associated with a less favorable prognosis compared to ypN0. In conclusion, the HER2 or TN group is highest for predicting ypN0, shown to be most prognostic of long-term survival similar to the patients with pN0. They could be omitted the axillary dissection.

Citation Format: Nakamura R, Yamamoto N, Miyaki T, Itami M. Prognostic impact of axillary lymph node status after neoadjuvant chemotherapy for patients with 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 P3-03-22.

Optimal surgical margin for infiltrative soft tissue sarcomas: Assessing the efficacy of excising beyond the infiltration

BACKGROUND

Tumor infiltration in soft tissue sarcoma (STS) is known to correlate with an inadequate surgical margin and poor local control. This study aims to determine whether the radiological infiltration (R-inf) in STS cor relates with histological infiltration (H-inf) and to devise methods to determine a resection margin for infiltrative STS.

METHODS

We reviewed the medical records of 145 patients with high-grade STS. We measured the R-inf on short-T1 inversion recovery or gadolinium-enhanced fat-suppressed (GdFS) magnetic resonance imaging. In addition, we assessed H-inf as the infiltrative growth of atypical tumor cells. The local control rate (LCR) was assessed using the Kaplan-Meier method.

RESULTS

A statistically significant positive correlation was found between H-inf and R-inf (P < 0.0001). The R-inf obtained from the GdFS images exhibited a stronger correlation with H-inf than that obtained from the short-T1 inversion recovery images. Univariate and multivariate analyses revealed that a positive H-inf significantly correlated with a poor LCR. Moreover, the contaminated margins, which included intrainfiltration margins, significantly correlated with a poor LCR compared with the wide margins.

CONCLUSIONS

R-inf as assessed by the GdFS images significantly correlates with H-inf, suggesting that we should exercise the infiltrative STS beyond their R-infs detected by the GdFS images.

Transformation of double-hit follicular lymphoma to plasmablastic lymphoma: a partial role of MYC gene rearrangement

Follicular lymphoma (FL) is genetically characterized by BCL2/IGH translocation. Some FL cases histologically transform to high-grade lymphoma, and the majority of cases transform to diffuse large B-cell lymphoma. We report herein an unusual FL case that transformed to plasmablastic lymphoma (PBL) with MYC gene rearrangement as early as 12 months after FL diagnosis. IGH/MYC translocation, the most common cytogenetic abnormality seen in de novo PBL, was also detected in the transformed tumor (double-hit lymphoma). The patient became resistant to chemotherapy and died 4 months after transformation. We speculate that the “second hit” of MYC rearrangement played a crucial role in PBL transformation (PBL-T) in this case. Highly specific three-color FISH analysis demonstrated the presence of BCL2/IGH/MYC triple fusion signals on a single chromosome as we expected, but BCL2/IGH and IGH/MYC fusion signals also coexisted in a single nucleus. The PBL-T tumor was genetically heterogeneous, despite being histologically quite homogeneous PBL. Surprisingly, three-color FISH analysis revealed that the preceding FL tumor was also genetically heterogeneous, simultaneously harboring BCL2/IGH, IGH/MYC and BCL2/IGH/MYC fusion signals (i.e. double-hit lymphoma), despite being histologically quite homogeneous FL. This suggests that MYC rearrangement played a partial role in PBL-T. Genetic instability including MYC rearrangement in the preceding FL tumor would contribute to PBL-T and poor outcome in this case. This study will broaden our understanding of the pathogenesis of high-grade transformation of FL and help improve patient outcome.

Abstract 3660: Can the presence of fusion genes in circulating cell-free DNA serve as potential biomarkers for Ewing's sarcoma

Background: Circulating cell-free DNA (cfDNA) is fragmented DNA derived from tumors that circulates in the blood of patients. With liquid biopsy, cfDNA has the potential to be used to monitor tumor burden in real time. Most reports have described that tumor-specific alterations in cfDNA are mutations, although little has been reported for the detection of tumor specific gene fusions. The objective of this study was to identify whether cfDNA can be used to detect tumor specific gene fusions and whether this would reflect the tumor burden of patients with Ewing's sarcoma.

Patients and Methods: Multiplex long-range genomic PCR was performed to detect patient-specific genomic breakpoints in eight patients. Probes for digital PCR were designed based on the genomic breakpoint of each patient. cfDNA was extracted from the serum of patients, which was drawn at multiple time-points (pretreatment, completion of the treatment, and/or relapse). cfDNA quantification was performed by digital PCR (BioRad Qx-200).

Results: Gene fusions in the cfDNA were detected in six (75%) of eight patients with high specificity. The relative gene fusion copy ratio (gene fusion copy number/wild KRAS copy number) was higher in the patients with M1b (extrapulmonary metastases at diagnosis) compared to the patients with M1a (pulmonary metastases at diagnosis) or M0 (no metastasis), although no significant relationship was observed between the relative gene fusion copy ratio and chemosensitivity. In each patient, the relative gene fusion copy ratio was the highest in pretreatment samples and decreased as the treatment progressed. Patients with relapse displayed an elevated relative gene fusion copy ratio in advance of clinical manifestation or elevation of lactase dehydrogenase.

Conclusion: The amount of cfDNA in the serum strongly correlated with the treatment stage and would be useful as an early biomarker for Ewing's sarcoma patients.

Citation Format: Shintaro Iwata, Hajime Kageyama, Tsukasa Yonemoto, Makiko Itami. Can the presence of fusion genes in circulating cell-free DNA serve as potential biomarkers for Ewing's sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3660.

Abstract P3-02-01: Impact of prognoses on the discrepancies in histological grade of breast cancer between core needle biopsy and surgical excision specimen

Purpose: The high reliability and utility of core needle biopsy (CNB) have been previously described. Histological grade in CNB is one of the main determinants of the need for neoadjuvant systemic therapy. Our aim in this study was to clarify the host and histopathological factors influencing the discrepancies in histological grade (HG) between CNB and surgically excision specimen (SES).

Methods: A total of 1342 operable invasive breast carcinoma biopsies were assessed and compared with surgical specimens in our hospital. Patients who required neoadjuvat chemotherapy were excluded. Histological grade (tubule formation, nuclear pleomorphism and mitotic index) was assessed between paired CNB and SET samples.

ER and PgR status were determined using immunohistochemistry(IHC). HER2 status was determined using IHC and scored from 0 to 3+. Fluorescence in-situ hybridization analysis was carried out in HER2 2+ cases. The cut off point for ER and PgR positivity was set at 1%.

Results: The clinicopathological characteristics of tumors showed in

Clinico-pathological characteristics of 1342 patients and tumors by discordance group between CNB and SES for histological grade  LL groupHH groupHL groupLLHgroupp valupTT1a31 (94%)0(0%)2(6%)0(0%)0.001 T1b162(92%)4(2%)1(1%)10(6%)  T1c421(79%)43(8%)14(3%)52(10%)  T2335(68%)63(13%)10(2%)82(17%)  T352(68%)8(10%)2(3%)15(19%)  T425(71%)4(11%)0(0%)6(17%) pNnegtive668(78%)73(9%)13(2%)101(12%)0.08 positive358(74%)49(10%)16(3%)64(13%) lynegative600(79%)6(4(8%)14(2%)85(11%)0.18 positive426(74%)58(10%)15(3%)80(14%) vnegative799(80%)81(5%)23(2%)98(10%)0.001 positive227(67%)41(12%)6(2%)67(20%) ER/PgRmegative82(33%)83(33%)13(5%)72(29%)0.001 positive944(86%)39(4%)16(1%)93(9%) HER2negative932(80%)86(7%)22(2%)121(10%)0.001 positive94(52%)36(20%)7(4%)44(24%) CNB;core needle biopsy, SES;surgical excision specimen, HH group (high grade in CNB/high grade in SES), LL group (low grade in CNB/low grade in SES), HL group (high grade in CNB/low grade in SES) and LH group (low grade in CNB/high grade in SES)

. The concordance rates of HG of luminal type, HER2 type luminal HER2 type and Triple negative type in CNB and SES were 91%, 64%, 73% and 66%, respectively (p&gt;0.001). Factors of discrepancy were T size, vessel invasion and ER/HER2 status for HG. The discrepancy factors were assessed with univariate and multivariate analysis. The underestimate and overestimate rates of HG in CNB compared to SES were7.5% and 1.3% in ER(+)HER2(-) type, 32%, and 3.1% in HER2 type, 22% and 4.3% in ER(+) HER2(+) type and 29% and 5.5% in Triple negative type(TN), respectively. The concordance rates of tubule formation, nuclear pleomorphism and mitotic index in CNB and SES were 81%, 97% and 93% in luminal type, 85%, 66% and 33% in HER2 type, 77%, 87% and 83% in luminal HER2 type and 82%, 67% and 73% in TN type respectively.

Conclusions: Using the largest known dataset to date of paired samples from a single institution, we evaluated the accuracy of CNB and the discrepancy factors between CNB and SES in breast cancer patients.

We conclude that CNB for histological grade assessment in patients with HER2 positive or TN breast cancer before neoadjuvant treatment should be used with caution.

Citation Format: Nakamura R, Yamamoto N, Miyaki T, Teranaka R, Itami M. Impact of prognoses on the discrepancies in histological grade of breast cancer between core needle biopsy and surgical excision specimen [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-02-01.

Impact of sentinel lymph node biopsy by ultrasound-guided core needle biopsy for patients with suspicious node positive breast cancer

PURPOSE

The purpose of this study was to investigate the accuracy of preoperative diagnostic tools for axillary lymph nodes (LNs) staging of breast cancer.

MATERIALS AND METHODS

A total of 2464 consecutive patients with operable breast cancer were prospectively identified at our institution between April 2012 and March 2017. Patients with suspicious axillary LN of breast cancer were assessed using preoperative ultrasound(US) or computed tomography (CT), underwent fine-needle aspiration cytology (FNA) or core needle biopsy (CNB). The inclusion criteria for both FNA and CNB were a cortical thickness >3 mm or abnormal morphological characteristics. Patients with biopsy-proven metastasis underwent axillary lymph node dissection (ALND), and those with a negative FNA or CNB underwent sentinel lymph node biopsy (SNB). If the SNB was positive, ALND was performed. Diagnostic accuracy for SNB was calculated for both FNA and CNB. In addition, the patients in this study were divided into two groups as follows: the cN0-FNA group (suspicious LN but negative FNA) and cN0-CNB group (suspicious LN but negative CNB).

RESULTS

A number of patients with negative US/CT findings of LNs were 1406, with 744 undergoing FNA and 272 undergoing CNB for suspicious LNs. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 65, 99, 99, 80, and 85% in FNA, and 87, 100, 100, 93 and 95% in CNB, respectively. SNB was performed in 172 (cN0-CNB group) of 272 CNB and 487 (cN0-FNA group) of 744 FNA patients. One hundred and seventy-two patients from the cN0-CNB group (Tis 6, T1 97, T2 66, T3 3 patients) treated with SNB were compared to 487 from the cN0-FNA group (Tis 21, T1 225, T2 233, T3 8 patients) in terms of number of LN metastasis. A number of patients with more than 3 positive SNB and positive LNs were 9 (5%) and 0 (0%) in cN0-CNB group, and 78 (16%) and 24 (5%) in cN0-FNA group, respectively. A number of patients who had complications such as haematoma and pain at the time of 7 to 14 days after CNB and FNA were 1 (0.5%) and 1 (0.5%) in cN0-CNB group, and were 0% and 0.2% in cN0-FNA group (p = 0.44), respectively.

CONCLUSIONS

The preoperative diagnosis of axillary LNs was influenced by the diagnostic tool used. CNB is a reliable method for the preoperative diagnosis of LN metastasis.

Successful treatment with biweekly CHOP for bone marrow relapse of blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological malignancy derived from precursors of plasmacytoid dendritic cells. The majority of patients initially respond to multi-agent chemotherapy, though most relapse within a year and the prognosis is very poor. We report a 67-year-old man with erythema on the right chest and a nasopharyngeal mass. Histological examination revealed a mass of tumor cells expressing CD4, CD56, and CD123, but neither CD3 nor CD20. He was diagnosed with BPDCN. Bone marrow involvement was not seen at diagnosis. He achieved complete remission (CR) with CHOP-like chemotherapy. After 1 year, he relapsed with a cutaneous tumor on the head, a nasopharyngeal tumor, and massive bone marrow involvement. Relapsed BPDCN is generally resistant to chemotherapy and the prognosis is dismal. However, he was successfully treated with biweekly CHOP therapy and achieved a second CR lasting 16 months.

Frequent Presence of Lymphovascular Invasion in Small Rectal Neuroendocrine Tumors on Immunohistochemical Analysis

Rectal neuroendocrine tumors (RNETs) have become common in recent years and are good candidates for endoscopic resection (ER). To achieve clear resection margins, more advanced techniques such as endoscopic submucosal dissection, endoscopic submucosal resection with a ligation device, and cap-assisted endoscopic mucosal resection are available for ER. After ER, lymphovascular invasion (LVI) is regarded as an important predictor of nodal metastasis. Previous studies have shown that small RNETs with LVI were uncommon (0-8.3%). However, using immunohistochemical analysis, a recent study revealed the frequent occurrence of LVI in small RNETs in a systematic manner (46.7%). There is a possibility that the actual detection rate of LVI in small RNETs is not always evaluated accurately because of the limited detection sensitivity of conventional hematoxylin-eosin staining. In addition, the correlation between LVI detected using immunohistochemical analysis and the development of metastasis remains unclear. Further prospective studies are required to clarify the role of LVI detected using immunohistochemical analysis.

Identification of novel mutations in Japanese ovarian clear cell carcinoma patients using optimized targeted NGS for clinical diagnosis

OBJECTIVE

Ovarian clear cell carcinoma (OCCC) is an aggressive ovarian cancer with a higher frequency in Japan and often becomes chemorefractory disease. Reliable genetic diagnosis is essential to affirm the success of precision medicine for OCCC treatment. The aim of this study is, therefore, to identify novel mutations in OCCCs and develop a feasible clinical next generation sequencing (NGS) approach using formalin-fixed paraffin-embedded (FFPE) rather than preferable but not always available fresh frozen (FF) samples.

METHODS

We optimized and evaluated exome analyses of 409 cancer-related genes using FFPE and FF DNA and analyzed NGS data to identify somatic mutations in Japanese OCCCs.

RESULTS

Sufficient and good quality DNAs from FFPE samples were extracted from 18 (FIGO Stage I: 12) out of 29 pairs of matched normal and OCCC for NGS (63%). The fine quality of extracted DNAs depended on the length of storage period (<2years storage). We also identified 45 somatic mutations in 34 genes including unreported variants from those FFPE DNA, in which somatic mutations in the PIK3CA gene was the most common (28%) as previously reported. Seven genes (PIK3CA, ARID1A, CTNNB1, CSMD3, LPHN3, LRP1B, and TP53) were mutated in at least two independent OCCCs. FF samples from 3 out of those 18 OCCCs were available and 13 out of 14 FFPE somatic mutations were confirmed.

CONCLUSIONS

We successfully identified novel genetic alterations in Japanese OCCCs and demonstrated a feasible clinical diagnostic procedure using targeted NGS for OCCC FFPE samples.

Enhanced detection of lymphovascular invasion in small rectal neuroendocrine tumors using D2-40 and Elastica van Gieson immunohistochemical analysis

Rectal neuroendocrine tumor (RNET) lymphovascular invasion (LVI) is regarded as an important predictor of nodal metastasis after endoscopic resection (ER). However, little is known about the frequency of immunohistochemical detection of LVI in RNETs. This study was performed to establish the actual detection of LVI rate in RNETs ≤10 mm and to evaluate associated clinical outcomes. We retrospectively reviewed the records for 98 consecutive patients treated by ER with a total of 102 RNETs ≤10 mm. Tissue sections were labeled with hematoxylin–eosin (HE) stain, the D2‐40 monoclonal antibody to evaluate lymphatic invasion, and Elastica van Gieson (EVG) stain to detect venous invasion. LVI detection rate by HE versus immunohistochemical analysis was compared. Follow‐up findings and clinical outcomes were also evaluated for 91 patients who were followed for ≥12 months. Lymphatic and venous invasion were detected using HE staining alone in 6.9% and 3.9% of patients, respectively, whereas they were detected using D2‐40 and EVG staining in 20.6% and 47.1% of the patients, respectively. Thus, the LVI detection frequency using D2‐40 and EVG staining (56.9%) was significantly higher than with HE (8.8%). Two out of seven patients who required additional surgery had regional lymph node metastases. However, among the 84 patients who were followed up without surgery, no distant metastases or recurrences were detected. Compared with HE staining, immunohistochemical analysis significantly increased the frequency of LVI detection in RNETs ≤10 mm. However, the clinical impact of LVIs detected using immunohistochemical analysis remains unclear. Clarification of the actual role of LVI using immunohistochemical analysis requires a patient long‐term follow‐up and outcomes.

[Primary gastrointestinal follicular lymphoma of the small intestine with massive hemorrhage: a report of three cases]

Primary gastrointestinal follicular lymphoma (FL) has an indolent clinical presentation and many of cases are diagnosed incidentally during routine endoscopic examinations. Herein, we present 3 cases with FL of the small intestine developed massive intestinal hemorrhage that necessitated blood transfusion. In all three patients, upper and lower endoscopic examinations failed to detect the bleeding sites. Eventually, video capsule endoscopies identified ulcerative lesions in the jejunum and biopsies using single- or double-balloon endoscopy confirmed the FL diagnosis in our three cases. The respective clinical stages according to the Lugano system were I, II-1 and II-1. PET-CT did not play a significant role in identifying the gastrointestinal lesions. Two patients received rituximab monotherapy and achieved a complete response. The other remains under observation after termination of antiplatelet drug therapy. Generally, the macroscopic appearance of multiple whitish nodules and the absence of symptoms represent the typical clinical picture of gastrointestinal FL. However, this study demonstrates that patients with ulcerative lesions may be at risk for massive bleeding. Further discussion is required to determine the optimal indications for total endoscopic examination of the small intestine.

Sendai virus-mediated expression of reprogramming factors promotes plasticity of human neuroblastoma cells

Neuroblastoma (NB) is the most common extracranial solid tumor that originates from multipotent neural crest cells. NB cell populations that express embryonic stem cell-associated genes have been identified and shown to retain a multipotent phenotype. However, whether somatic reprogramming of NB cells can produce similar stem-cell like populations is unknown. Here, we sought to reprogram NB cell lines using an integration-free Sendai virus vector system. Of four NB cell lines examined, only SH-IN cells formed induced pluripotent stem cell-like colonies (SH-IN 4F colonies) at approximately 6 weeks following transduction. These SH-IN 4F colonies were alkaline phosphatase-positive. Array comparative genomic hybridization analysis indicated identical genomic aberrations in the SH-IN 4F cells as in the parental cells. SH-IN 4F cells had the ability to differentiate into the three embryonic germ layers in vitro, but rather formed NBs in vivo. Furthermore, SH-IN 4F cells exhibited resistance to cisplatin treatment and differentiated into endothelial-like cells expressing CD31 in the presence of vascular endothelial growth factor. These results suggest that SH-IN 4F cells are partially reprogrammed NB cells, and could be a suitable model for investigating the plasticity of aggressive tumors.

Abstract P2-04-08: Accuracy of estrogen receptor, progesterone receptor, HER2 Status and Ki67 labeling index between core needle and surgical excisional tumour in 910 patients with breast cancer

Purpose

Accurate determination of ER, PgR, HER2 status and Ki67 labeling index was very important in making decision for adjuvant and neoadjuvant treatment for patients with breast cancer. However discordance of ER, PgR, HER2 status and Ki67 labeling index (Ki67-LI) between core needle biopsy (CNB) and surgical specimens (SSp) varied among reported studies.

The aim of the present study was to compare the accuracy of CNB with that of SSp for ER, PgR,HER-2 status, Ki67-LI detection in breast cancer.

Patients and methods

All patients diagnosed with an early breast cancer in our Cancer Center Hospital between January 2005 and May 2014 was included but exclusion criteria of patients with large tumour requiring neoadjuvant chemotherapy. All CNB were performed under ultrasound guidance, with at least four 14-gauce core biopsies being obtained for pathological examination. ER, PgR, HER-2 status and Ki67-LI were assessed in CNB and in SSp. ER and PgR were determined by

Immunohistochemistry (IHC). The cut points for ER and PgR positive was10%. The cut point for Ki67-LI high expression was 20%. HER2 was determined by IHC and scored from 0 to 3+. FISH analysis was carried out in HER2 2+ cases and in discordant cases.

Results

A total of 910 patients were assessed. CNB can be used with confidence for ER and HER2 determination. Rates for sensitivity, specificity, negative predictive value and positive predictive value for CNB compared with SSp are 99.3%,95.6%,97.2%,98.5% for ER, 94.5%,81.8%,88.2%,90.7% for PgR ,93.0%,99.1%,99.6%,93.9% for HER2, and 87.7%,69.8%,81.1%,79.4% for Ki67-LI, respectively. Specially, the most impact factor of discordance for Ki67-LI and HER2 is Tumour size and that for ER and PgR is lobular carcinoma.

Conclusion

CNB can be used with confidence for ER and HER2 determination. For PgR and Ki67-LI due to substantial discordance results from CNB should be used with caution.

Citation Format: Rikiya Nakamura, Naohito Yamamoto, Yoshiyuki Itookubo, Ayako Nakagawa, Makiko Itami. Accuracy of estrogen receptor, progesterone receptor, HER2 Status and Ki67 labeling index between core needle and surgical excisional tumour in 910 patients with breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-04-08.

Endobronchial ultrasound-guided transbronchial needle aspiration in a patient with pericardial mesothelioma

Pericardial mesothelioma is a very rare pericardial tumor. Diagnosing pericardial disease can be challenging, and obtaining an antemortem diagnosis of pericardial mesothelioma is particularly difficult. We herein report the case of a 60-year-old man with pericardial mesothelioma diagnosed on endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Chest computed tomography showed a mass surrounding the pericardium, and EBUS-TBNA of the right inferior paratracheal and subcarinal stations was consequently performed. No uptake was noted on (18)F-fluorodeoxy glucose positron emission tomography, other than in the pericardial mass. The results of histological and immunohistochemical examinations indicated the features of malignant mesothelioma. We therefore diagnosed the patient with pericardial mesothelioma, which was subsequently confirmed at autopsy.