Targeted next-generation sequencing of Japanese patients with sinonasal mucosal melanomas identifies frequent NRAS and CTNNB1 mutations

OBJECTIVE

Mucosal melanoma is a rare malignancy; however, the reported incidence rate of mucosal melanoma is higher in Asians than in Caucasians. Sinonasal mucosal melanoma (SNMM) is an aggressive malignancy with a poor prognosis due to distant metastasis. Systemic therapy with BRAF inhibitor and MEK inhibitor is one of the standards of care for cutaneous melanoma patients with BRAF V600 mutations. However, no molecular targeted therapy for patients with mucosal melanoma has been established. Relatively few studies have described the genetic mutations associated with mucosal melanoma because of its low frequency. Furthermore, to the best of our knowledge, the genetic mutations among Japanese patients have not been reported. Therefore, in the current study, we evaluated the genetic and clinicopathological characteristics of patients with SNMM.

METHODS

A total of 18 tissue samples obtained from patients with SNMM were analyzed for genetic mutations based on targeted next-generation sequencing to investigate the driver of tumorigenesis and/or candidate genes for predicting clinical outcomes in SNMM. We also performed immunohistochemistry for patients identified with CTNNB1 mutations.

RESULTS

Eight of the 18 (44 %) patients had genetic mutations. The most frequent mutation was NRAS (6/18, 33 %), followed by CTNNB1 (2/18, 11 %) and BRAF (1/18, 5.6 %). One patient had both NRAS and CTNNB1 mutations. Clinical outcomes did not differ significantly between those with and without genetic mutations. NRAS mutations were associated with relatively higher T classification and worse survival rates, although the differences were not significant. The nuclear translocation of β-catenin was detected in both tumors with CTNNB1 mutations. The amino acid change in the BRAF mutation was K601R in exon 15. In the current study, no BRAF V600 mutations were detected.

CONCLUSION

Genetic mutations were not significantly associated with clinical outcomes. However, NRAS mutations may be a prognostic predictor and CTNNB1 mutation may be a treatment effector for immune check inhibitors. A larger prospective study is required to clarify the clinical importance of genetic mutations in patients with SNMM.

Concurrent targeting of GSK3 and MEK as a therapeutic strategy to treat pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies worldwide. However, drug discovery for PDAC treatment has proven complicated, leading to stagnant therapeutic outcomes. Here, we identify Glycogen synthase kinase 3 (GSK3) as a therapeutic target through a whole-body genetic screening utilizing a '4-hit' Drosophila model mimicking the PDAC genotype. Reducing the gene dosage of GSK3 in a whole-body manner or knocking down GSK3 specifically in transformed cells suppressed 4-hit fly lethality, similar to Mitogen-activated protein kinase kinase (MEK), the therapeutic target in PDAC we have recently reported. Consistently, a combination of the GSK3 inhibitor CHIR99021 and the MEK inhibitor trametinib suppressed the phosphorylation of Polo-like kinase 1 (PLK1) as well as the growth of orthotopic human PDAC xenografts in mice. Additionally, reducing PLK1 genetically in 4-hit flies rescued their lethality. Our results reveal a therapeutic vulnerability in PDAC that offers a treatment opportunity for patients by inhibiting multiple targets.

Expression Analysis of Early Metastatic Seeding of Colorectal Cancer

BACKGROUND

Distant metastasis is the leading cause of death in patients with colorectal cancer (CRC). Tumor dissemination for metastasis formation occurs in advanced cancers and also during early stages of tumorigenesis. Here, we investigated the genes involved in early metastatic seeding of CRC using gene expression analysis.

PATIENTS AND METHODS

We performed a cDNA microarray using specimens resected from stages I-II CRC with and without metachronous metastatic recurrence. For the candidate genes, we immunohistochemically validated protein expression using a tissue microarray of stages I-III CRC.

RESULTS

The expression of TROP2, VWCE, and BMP7 was upregulated in the recurrence group rather than in the non-recurrence group. Protein expression analysis revealed significant association of these genes with distant metastatic recurrence. The specimens with high expression of BMP7 showed worse recurrence-free survival (RFS; p = 0.02). Those with high expression of TROP2 and VWCE showed worse overall survival (OS) and RFS (TROP2: p = 0.01 and p = 0.03; VWCE: p < 0.05 and p < 0.001, respectively). In the multivariate analysis, high expression of VWCE and BMP7 was an independent predictor of recurrence [VWCE: hazard ratio (HR) 3.41, p < 0.001; BMP7: HR 2.93, p = 0.005]. In contrast, TROP2 was an independent prognostic factor for OS (HR 4.58, p = 0.03).

CONCLUSIONS

Gene expression analysis revealed that TROP2, VWCE, and BMP7 were involved in early metastatic seeding. The high expression of these genes may warrant careful surveillance or adjuvant therapy, even in stages I-II CRC cases.

Impact of Neutrophil Extracellular Traps Identified by Citrullinated Histone H3 Immunohistochemistry for Postoperative Prognosis in Patients with Extrahepatic Cholangiocarcinomas

BACKGROUND

Neutrophil extracellular traps (NETs) are extracellular chromatin structures composed of cytoplasmic, granular, and nuclear components of neutrophils. Recently, NETs have received much attention for their role in tumor biology; however, their impact on the postoperative prognosis of patients with extrahepatic cholangiocarcinomas (EHCCs) remains unclear. The purpose of this study was to clarify the impact of NETs identified by immunohistochemical citrullinated histone H3 (Cit-H3) staining on postoperative overall survival (OS) in patients with perihilar cholangiocarcinoma (PHCC) and distal cholangiocarcinoma (DCC).

METHODS

This study included 318 patients with EHCC (PHCC, n = 192; DCC, n = 126) who underwent surgical resection with curative intent. Neutrophils and NETs were identified by immunohistochemistry using antibodies against CD15 and Cit-H3, respectively. Based on the distribution of CD15 and Cit-H3 expression in the tumor bed, the patients were classified into four groups: one negative group and three subgroups of the positive group (diffuse, intermediate, and focal subgroups).

RESULTS

No significant difference was found in the postoperative OS rate depending on the distribution of CD15 expression in patients with PHCC or DCC. However, the three subgroups with positive Cit-H3 expression had significantly poorer OS than the negative group for both PHCC and DCC. Moreover, positive Cit-H3 was an independent OS factor in the multivariable analyses of PHCC (hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.11-2.59, P = 0.0115) and DCC (HR 2.03; 95% CI 1.21-3.42, P = 0.0057).

CONCLUSIONS

The presence of NETs in the tumor microenvironment may have adverse prognostic effects in patients with EHCCs.

Impact of the quality of resected thyroid cancer tissue sample on next-generation sequencing testing

Activating rearranged during transfection (RET) proto-oncogene alterations can be identified using next-generation sequencing (NGS) of tumor DNA/RNA. We assessed factors associated with NGS (Oncomine Dx Target Test [ODxTT]) success for resected thyroid cancer (TC) specimens, including sample age, processing conditions, and DNA/RNA quality. TC samples were from three Japanese hospitals, with sample age <1-<10 years, fixative 10%/15% neutralized buffered formalin (NBF), and fixation time ≤48 h/>48 h-≤72 h. NGS success rate was defined as the percentage of samples returning validated NGS results (RET fusion-positive/negative [RNA] or RET mutation-positive/negative [DNA], detected using ODxTT). DNA/RNA quality was assessed with indexes based on electrophoresis (DNA/RNA integrity number, DV200 ) and quantitative polymerase chain reaction (DNA/RNA integrity score [ddCq/ΔCq]). NGS success rate (N = 202) was 90%/93% (DNA/RNA) overall, 98%-100% (DNA and RNA) for samples <3 years old, and 91% (DNA and RNA) for samples ≥3-<5 years old fixed in 10% NBF for ≤48 h. Multivariate logistic regression analysis identified ddCq and ΔCq as significant predictors of DNA and RNA NGS success rates, respectively. Quality assessment of nucleic acid extracted from archival tissue samples is important for achieving high NGS success rates in clinical practice, especially for samples ≥3 years old.

Polymorphisms of the PD-L1 gene 3'-untranslated region are associated with the expression of PD-L1 in non-small cell lung cancer

Recent results show that polymorphisms of programmed death ligand 1 (PD-L1, also known as CD274 or B7-H1) might be used as a possible marker for effectiveness of chemotherapy and cancer risk. However, the effect of PD-L1 gene variations on PD-L1 expression remain unclear. Given the post-transcriptional machinery in tumor PD-L1 expression, we investigated single nucleotide polymorphisms (SNPs) in the 3'-untranslated region (3'-UTR) of the PD-L1 gene, rs4143815 and rs4742098, using formalin-fixed paraffin-embedded sections of 154 patients with non-small cell lung cancers (NSCLCs). In rs4143815, the GG genotype showed significant association with PD-L1 expression (P = 0.032). In rs4742098, the AA genotype was significantly associated with histology and PD-L1 expression (P = 0.022 and P = 0.008, respectively). In multivariate logistic regression analysis, the AA genotype in rs4742098 was correlated with PD-L1 expression (odds ratio 0.408, P = 0.048). Interestingly, approximately 10% of the NSCLC cases showed somatic mutation when we compared genotypes of these SNPs between NSCLC tissues and non-tumor tissues from the same patients. In addition, cases with somatic mutation showed higher levels of PD-L1 expression than cases with germline mutation in rs4143815 GG. In conclusion, we demonstrated that the rs4143815 and rs4742098 SNPs in the 3'-UTR of PD-L1 were associated with tumor PD-L1 expression in NSCLCs.

Clinical practice guidelines for molecular tumor markers, 2nd edition review part 1

With advances in gene and protein analysis technologies, many target molecules that may be useful in cancer diagnosis have been reported. Therefore, the "Tumor Marker Study Group" was established in 1981 with the aim of "discovering clinically" useful molecules. Later, the name was changed to "Japanese Society for Molecular Tumor Marker Research" in 2000 in response to the remarkable progress in gene-related research. Currently, the world of cancer treatment is shifting from the era of representative tumor markers of each cancer type used for tumor diagnosis and treatment evaluation to the study of companion markers for molecular-targeted therapeutics that target cancer cells. Therefore, the first edition of the Molecular Tumor Marker Guidelines, which summarizes tumor markers and companion markers in each cancer type, was published in 2016. After publication of the first edition, the gene panel testing using next-generation sequencing became available in Japan in June 2019 for insured patients. In addition, immune checkpoint inhibitors have been indicated for a wide range of cancer types. Therefore, the 2nd edition of the Molecular Tumor Marker Guidelines was published in September 2021 to address the need to revise the guidelines. Here, we present an English version of the review (Part 1) of the Molecular Tumor Marker Guidelines, Second Edition.

Exhaustion, rather than lack of infiltration and persistence, of CAR-T cells hampers the efficacy of CAR-T therapy in an orthotopic PDAC xenograft model

Chimeric antigen receptor T-cell (CAR-T) therapy has demonstrated impressive success in the treatment of patients with hematologic tumors yet achieved very limited efficacy for solid tumors due to hurdles unique to solid tumors. It is also noted that the tumor microenvironment composition varies between tumor type, which again imposes unique set of hurdles in each solid tumor. Therefore, elucidation of individual hurdles is key to achieving successful CAR-T therapy for solid tumors. In the present study, we employed an orthotopic human PDAC xenograft model, in which quantitative, spatial and functional dynamics of CAR-T cells in tumor tissues were analyzed to obtain insights into ways of overcoming PDAC related hurdles. Contrary to previous studies that demonstrated a limited persistency and infiltration of CAR-T cells in many solid tumors, they persist and accumulated in PDAC tumor tissues. Ex vivo analysis revealed that CAR-T cells that had been recovered at different time points from mice bearing an orthotopic PDAC tumor exhibited a gradual loss of tumor reactivity. This loss of tumor reactivity of CAR-T cells was associated with the increased expression of AMP-activated protein kinase and Mitofusin 1/ Dynamin-related protein 1 ratio.

Postoperative Prognosis According to Pathologic Categorization of Desmoplastic Reaction in Patients with Extrahepatic Cholangiocarcinoma

BACKGROUND

Recent studies have demonstrated the importance of desmoplastic reaction (DR) in predicting postoperative prognosis for patients with colorectal carcinoma. However, the impact of DR on the prognosis of extrahepatic cholangiocarcinomas (EHCCs) is not established. This study aimed to clarify the associations of pathologic DR categories with clinicopathologic factors and postoperative prognosis of perihilar cholangiocarcinoma (PHCC) and distal cholangiocarcinoma (DCC).

METHODS

A pathologic review of 174 patients with PHCC and 109 patients with DCC who underwent surgical resection was performed. The patients were classified into three DR categories (immature, intermediate, and mature) based on the histologic features within the fibrotic stroma in the invasive front. The association between DR categories and the distribution of fibroblasts with anti-α-smooth muscle actin (SMA) expression, seeming to be tumor-promoting cancer-associated fibroblasts (CAFs), was evaluated in 191 tissue microarray specimens of EHCCs.

RESULTS

Intermediate/immature DR categories were significantly associated with a more invasive nature, including higher pT and pN stages and more tumor buds than the mature category in both PHCC and DCC. The DR categories could stratify overall survival (OS) and relapse-free survival (RFS) in both PHCC and DCC patients. In the multivariate analysis, the DR category was an independent prognostic factor for OS and RFS in both PHCC and DCC (p < 0.001). The mature and immature DR categories were significantly associated respectively with the confined and pervasive distribution of fibroblasts with α-SMA expression.

CONCLUSION

In patients with EHCCs, DR categorization was an independent prognostic factor reflecting the distribution of tumor-promoting CAFs in the invasive front.

Targeted next-generation sequencing for detection of PIK3CA mutations in archival tissues from patients with Klippel-Trenaunay syndrome in an Asian population : List the full names and institutional addresses for all authors

BACKGROUND

Klippel-Trenaunay syndrome (KTS) is a rare slow-flow combined vascular malformation with limb hypertrophy. KTS is thought to lie on the PIK3CA-related overgrowth spectrum, but reports are limited. PIK3CA encodes p110α, a catalytic subunit of phosphatidylinositol 3-kinase (PI3K) that plays an essential role in the PI3K/AKT/mammalian target of rapamycin (mTOR) signaling pathway. We aimed to demonstrate the clinical utility of targeted next-generation sequencing (NGS) in identifying PIK3CA mosaicism in archival formalin-fixed paraffin-embedded (FFPE) tissues from patients with KTS.

RESULTS

Participants were 9 female and 5 male patients with KTS diagnosed as capillaro-venous malformation (CVM) or capillaro-lymphatico-venous malformation (CLVM). Median age at resection was 14 years (range, 5-57 years). Median archival period before DNA extraction from FFPE tissues was 5.4 years (range, 3-7 years). NGS-based sequencing of PIK3CA achieved an amplicon mean coverage of 119,000x. PIK3CA missense mutations were found in 12 of 14 patients (85.7%; 6/8 CVM and 6/6 CLVM), with 8 patients showing the hotspot variants E542K, E545K, H1047R, and H1047L. The non-hotspot PIK3CA variants C420R, Q546K, and Q546R were identified in 4 patients. Overall, the mean variant allele frequency for identified PIK3CA variants was 6.9% (range, 1.6-17.4%). All patients with geographic capillary malformation, histopathological lymphatic malformation or macrodactyly of the foot had PIK3CA variants. No genotype-phenotype association between hotspot and non-hotspot PIK3CA variants was found. Histologically, the vessels and adipose tissues of the lesions showed phosphorylation of the proteins in the PI3K/AKT/mTOR signaling pathway, including p-AKT, p-mTOR, and p-4EBP1.

CONCLUSIONS

The PI3K/AKT/mTOR pathway in mesenchymal tissues was activated in patients with KTS. Amplicon-based targeted NGS could identify low-level mosaicism from low-input DNA extracted from FFPE tissues, potentially providing a diagnostic option for personalized medicine with inhibitors of the PI3K/AKT/mTOR signaling pathway.

Drosophila Screening Identifies Dual Inhibition of MEK and AURKB as an Effective Therapy for Pancreatic Ductal Adenocarcinoma

Significant progress has been made in understanding the pathogenesis of pancreatic ductal adenocarcinoma (PDAC) by generating and using murine models. To accelerate drug discovery by identifying novel therapeutic targets on a systemic level, here we generated a Drosophila model mimicking the genetic signature in PDAC (KRAS, TP53, CDKN2A, and SMAD4 alterations), which is associated with the worst prognosis in patients. The '4-hit' flies displayed epithelial transformation and decreased survival. Comprehensive genetic screening of their entire kinome revealed kinases including MEK and AURKB as therapeutic targets. Consistently, a combination of the MEK inhibitor trametinib and the AURKB inhibitor BI-831266 suppressed the growth of human PDAC xenografts in mice. In patients with PDAC, the activity of AURKB was associated with poor prognosis. This fly-based platform provides an efficient whole-body approach that complements current methods for identifying therapeutic targets in PDAC.

SIGNIFICANCE

Development of a Drosophila model mimicking genetic alterations in human pancreatic ductal adenocarcinoma provides a tool for genetic screening that identifies MEK and AURKB inhibition as a potential treatment strategy.

Protein-Ligand Interaction Analyses with Nuclear Magnetic Resonance Spectroscopy Enhanced by Dissolution Triplet Dynamic Nuclear Polarization

Solution-state nuclear magnetic resonance spectroscopy (NMR) is a powerful method for the analysis of intermolecular interactions within a biomolecular system. However, low sensitivity is one of the major obstacles of NMR. We improved the sensitivity of solution-state ¹³C NMR for the observation of intermolecular interactions between protein and ligand using hyperpolarized solution samples at room temperature. Eutectic crystals composed of ¹³C-salicylic acid and benzoic acid doped with pentacene were hyperpolarized by dynamic nuclear polarization using photoexcited triplet electrons, and a ¹³C nuclear polarization of 0.72 ± 0.07% was achieved after dissolution. The binding of human serum albumin and ¹³C-salicylate was observed with several hundred times sensitivity enhancement under mild conditions. The established ¹³C NMR was applied for pharmaceutical NMR experiments by observation of the partial return of the ¹³C chemical shift of salicylate by competitive binding with other non-isotope-labeled drugs.

Assessment for the timing of comprehensive genomic profiling tests in patients with advanced solid cancers

Comprehensive genomic profiling (CGP) tests have been covered by public insurance in Japan for patients with advanced solid tumors who have completed or are completing standard treatments or do not have them. Therefore, genotype-matched drug candidates are often unapproved or off-label, and improving clinical trial access is critical, involving the appropriate timing of CGP tests. To address this issue, we analyzed the previous treatment data for 441 patients from an observational study on CGP tests discussed by the expert panel at Hokkaido University Hospital between August 2019 and May 2021. The median number of previous treatment lines was two; three or more lines accounted for 49%. Information on genotype-matched therapies was provided to 277 (63%). Genotype-matched clinical trials were ineligible because of an excess number of previous treatment lines or use of specific agents were found in 66 (15%) patients, with the highest proportion in breast and prostate cancers. Many patients met the exclusion criteria of one to two or more treatment lines across cancer types. In addition, previous use of specific agents was a frequent exclusion criterion for breast, prostate, colorectal, and ovarian cancers. The patients with tumor types with a low median number (two or fewer) of previous treatment lines, including most rare cancers, primary unknown cancers, and pancreatic cancers, had significantly fewer ineligible clinical trials. The earlier timing of CGP tests may improve access to genotype-matched clinical trials, with their proportion varying by cancer type. Each relevant society needs to advocate the desirable timing of CGP testing nationwide.

CCR7 Mediates Cell Invasion and Migration in Extrahepatic Cholangiocarcinoma by Inducing Epithelial-Mesenchymal Transition

The epithelial-mesenchymal transition (EMT) contributes to the metastatic cascade in various tumors. C-C chemokine receptor 7 (CCR7) interacts with its ligand, chemokine (C-C motif) ligand 19 (CCL19), to promote EMT. However, the association between EMT and CCR7 in extrahepatic cholangiocarcinoma (EHCC) remains unknown. This study aimed to elucidate the prognostic impact of CCR7 expression and its association with clinicopathological features and EMT in EHCC. The association between CCR7 expression and clinicopathological features and EMT status was examined via the immunohistochemical staining of tumor sections from 181 patients with perihilar cholangiocarcinoma. This association was then investigated in TFK-1 and EGI-1 EHCC cell lines. High-grade CCR7 expression was significantly associated with a large number of tumor buds, low E-cadherin expression, and poor overall survival. TFK-1 showed CCR7 expression, and Western blotting revealed E-cadherin downregulation and vimentin upregulation in response to CCL19 treatment. The wound healing and Transwell invasion assays revealed that the activation of CCR7 by CCL19 enhanced the migration and invasion of TFK-1 cells, which were abrogated by a CCR7 antagonist. These results suggest that a high CCR7 expression is associated with an adverse postoperative prognosis via EMT induction and that CCR7 may be a potential target for adjuvant therapy in EHCC.

Guidelines for Handling of Cytological Specimens in Cancer Genomic Medicine

Rapid advances are being made in cancer drug therapy. Since molecularly targeted therapy has been introduced, personalized medicine is being practiced, pathological tissue from malignant tumors obtained during routine practice is frequently used for genomic testing. Whereas cytological specimens fixed mainly in alcohol are considered to be more advantageous in terms of preservation of the nucleic acid quality and quantity. This article is aimed to share the information for the proper handling of cytological specimens in practice for genomic medicine based on the findings established in "Guidelines for Handling of Cytological Specimens in Cancer Genomic Medicine (in Japanese)" published by the Japanese Society of Clinical Cytology in 2021. The three-part practical guidelines are based on empirical data analyses; Part 1 describes general remarks on the use of cytological specimens in cancer genomic medicine, then Part 2 describes proper handling of cytological specimens, and Part 3 describes the empirical data related to handling of cytological specimens. The guidelines indicated proper handling of specimens in each fixation, preparation, and evaluation.

Identification of antibody against wingless‑type MMTV integration site family member 7B as a biliary cancer tumor marker

Biliary cancer has a poor prognosis due to a lack of specific biomarkers and difficulty in diagnosis. The present study aimed to identify serum tumor markers for the diagnosis of biliary cancer via serological identification of antigens by recombinant cDNA expression cloning. Wingless‑type MMTV integration site family, member 7 (WNT7B) was identified as a target antigen, suggesting the presence of serum antibodies against this antigen. Deletion mutants were then prepared to evaluate the response to serum antibodies. When serum antibody levels against WNT7B deletion mutants (WNT7B_-92‑2, _-92‑260, _2-260 and _184-260) were examined using amplified luminescence proximity homogeneous assay‑linked immunosorbent assay, the levels of the antibody against WNT7B with amino acids 184‑260 were higher in patients with biliary cancer than in healthy donors. Therefore, the region covering residues 184‑260 of WNT7B was decomposed to generate seven peptides, and the levels of antibodies against these peptides were measured. Among them, the levels of antibodies against WNT7B_234‑253 and WNT7B_244‑260 were higher in patients with biliary cancers than in healthy donors (WNT7B_234‑253, P=0.0009; WNT7B_244‑260, P=0.0005). The levels of the antibody against the former were specifically high in patients with biliary cancer but not in those with esophageal, gastric, colorectal, pancreatic, or breast cancer. Furthermore, analysis by the cutoff value of WNT7B_234‑253 defined by ROC showed a high sensitivity of 70% in patients with biliary cancer. Therefore, the serum levels of the antibody against WNT7B_234‑253 may be useful as a marker for biliary cancer diagnosis.

Evaluation of 95-Gene Classifier of Formalin-fixed Paraffin-embedded Tissues in ER-positive, HER2-negative, and Node-negative Breast Cancer

BACKGROUND/AIM

A subset of patients with estrogen receptor (ER)-positive, HER2-negative, and node-negative breast cancer experience recurrences. Predicting patients who will have recurrences within 5 years of surgery is essential so that patients can be selected to receive adjuvant chemotherapy. The 95-gene classifier (95-GC) has been validated as a method to differentiate patients into high and low-risk groups for early recurrence.

PATIENTS AND METHODS

In this study, we performed 95-GC analysis on 56 formalin-fixed paraffin-embedded (FFPE) tissue samples from patients who underwent surgery for ER-positive, HER2-negative, and node-negative breast cancer and did not receive adjuvant chemotherapy. We associated the obtained high- and low-risk groups with clinicopathological characteristics and recurrence-free survival (RFS).

RESULTS

We classified 12 out of 56 patients into the high-risk recurrence group. We found significantly higher KI67 scores in patients in the high-risk group. Other clinicopathological characteristics were not associated with the 95-GC risk groups. Patients in the 95-GC low-risk group had a significantly better prognosis than those in the high-risk group (p=0.0387). The 5-year RFS rate was 97.6% in the low-risk group and 74.1% in the high-risk group, while the 10-year RFS rates were 90.1% and 74.1%, respectively.

CONCLUSION

The 95-GC score can accurately predict RFS within 5 years of surgery for ER-positive, HER2-negative, and node-negative breast cancer using FFPE tissue samples. These prediction models could help assign patients to the most effective treatment regimen.

Tumor Growth Suppression of Pancreatic Cancer Orthotopic Xenograft Model by CEA-Targeting CAR-T Cells

Chimeric antigen receptor engineered T cell (CAR-T) therapy has high therapeutic efficacy against blood cancers, but it has not shown satisfactory results in solid tumors. Therefore, we examined the therapeutic effect of CAR-T therapy targeting carcinoembryonic antigen (CEA) in pancreatic adenocarcinoma (PDAC). CEA expression levels on the cell membranes of various PDAC cell lines were evaluated using flow cytometry and the cells were divided into high, medium, and low expression groups. The relationship between CEA expression level and the antitumor effect of anti-CEA-CAR-T was evaluated using a functional assay for various PDAC cell lines; a significant correlation was observed between CEA expression level and the antitumor effect. We created orthotopic PDAC xenograft mouse models and injected with anti-CEA-CAR-T; only the cell line with high CEA expression exhibited a significant therapeutic effect. Thus, the therapeutic effect of CAR-T therapy was related to the target antigen expression level, and the further retrospective analysis of pathological findings from PDAC patients showed a correlation between the intensity of CEA immunostaining and tumor heterogeneity. Therefore, CEA expression levels in biopsies or surgical specimens can be clinically used as biomarkers to select PDAC patients for anti-CAR-T therapy.

Budget impact analysis of next-generation sequencing versus sequential single-gene testing in Japanese patients with advanced non-small-cell lung cancer

BACKGROUND

Identification of genomic alterations (e.g., EGFR, ALK, ROS1, BRAF, NTRK, and MET) is essential for initiating targeted therapy in patients with advanced non-small-cell lung cancer (aNSCLC). This study estimated the budget impact of using the sequential single-gene (SSG) test, which tests for each mutation one at a time, versus next-generation sequencing (NGS), which tests for all mutations at the same time, among newly diagnosed patients with aNSCLC from a Japanese healthcare payer's perspective.

METHODS

A budget impact model (BIM) was used to determine the expected budget impact associated with NGS for newly diagnosed aNSCLC in Japan over a 3-year period. The BIM compared the total costs (biopsy, testing, and treatment) and average turnaround time of "future NGS" and "current NGS" versus SSG testing.

RESULTS

The adoption of current NGS over SSG testing had a budget impact of -0.24%, but adoption of future NGS over SSG testing had a budget impact of +4.33% across a 3-year time horizon on the Japanese budget for aNSCLC treatment. The adoption of current or future NGS over SSG testing would shorten the average turnaround time for testing.

CONCLUSIONS

The adoption of current NGS over SSG testing would slightly decrease the yearly costs. However, the adoption of future or current NGS over SSG testing would shorten the average turnaround time, enabling faster identification of genomic alterations and earlier initiation of treatment for aNSCLC patients in Japan.

Deep fibrous histiocytoma of the index finger: a case report

Our patient presented with an elastic soft mass of his left index finger. Hematoxylin and eosin staining showed a high cellular density with spindle-shaped cells in a storiform pattern. Immunohistochemical staining was positive for CD68, factor XIIIa and α-smooth muscle actin, and negative for CD34, STAT6, S100 protein, and desmin.

Germline PRDM1 Variant rs2185379 in Long-Term Recurrence-Free Survivors of Advanced Ovarian Cancer

PURPOSE

To identify the germline genetic characteristics of long-term recurrence-free survivors that can be applied to establishing a new strategy for curing advanced cancer, we investigated the whole-genome single nucleotide variants of ovarian cancer patients.

PATIENTS AND METHODS

DNA specimens were obtained from rare long-term recurrence-free survivors with FIGO stage III-IV ovarian cancer with no recurrence for 8-23 years after primary treatments for a whole-genome analysis of approximately 660,000 single nucleotide variants. We then established a mouse model with a notable gene alteration by CRISPR/Cas9 to confirm the biological role.

RESULTS

The long-term recurrence-free survivors more frequently had germline heterozygous variant rs2185379 of the PRDM1 gene exon than patients with early recurrence (6.8-fold, P=0.013) and the general population. In the mouse model, primary intraperitoneal disseminated tumors of allograft ID8 were significantly smaller in the germline heterozygous rs2185379 group than in the wild-type group (57.4% decrease, P=0.008). Immunohistochemistry showed that the area of distribution of infiltrating T lymphocytes with positive CD8 staining was significantly increased in the germline heterozygous rs2185379 group in comparison to the wild-type group.

CONCLUSION

Germline heterozygous rs2185379 in PRDM1 is correlated with an excellent prognosis and can be used to establish a new strategy for treating advanced ovarian cancer.

Notch pathway regulates osimertinib drug‐tolerant persistence in EGFR ‐mutated non‐small cell lung cancer

Osimertinib is a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) that has shown marked antitumor activity in patients with EGFR-mutated non-small-cell lung cancer (NSCLC). However, these effects are transient and most patients develop resistance. Reversible drug-tolerant persister (DTP) cells are defined as a small subpopulation of cells with markedly reduced sensitivity and non-genetic acquired resistance to EGFR-TKIs. Notch is a transmembrane receptor that plays an important role in tumorigenesis. We previously reported that there is significant crosstalk between the Notch and EGFR pathways in NSCLC. Moreover, the Notch pathway is associated with resistance to previous-generation EGFR-TKIs. However, the role of Notch in osimertinib resistance is not fully understood. In this study, we evaluated whether Notch is involved in osimertinib resistance. We show that NOTCH1 and Notch target genes are upregulated in osimertinib DTP cells, and that the addition of a γ-secretase inhibitor (GSI), a Notch inhibitor, impairs drug-tolerant persistence in vitro and in vivo. Compared with osimertinib, combined GSI and osimertinib suppress phospho-ERK partly by enhancing DUSP1 expression. Furthermore, Notch1 and HES1 were upregulated after EGFR-TKI treatment in half of human EGFR-mutated NSCLC tumor tissues. These results suggest that the combination of GSI and osimertinib may be a potential therapy for EGFR-mutated NSCLC.

The prognosis of endometrial cancers stratified with conventional risk factors and modified molecular classification

This study aimed to validate the Proactive Molecular Risk Classifier for Endometrial Cancer, a modified version of The Cancer Genome Atlas, using data from 184 patients with endometrial cancer (median age: 57.5 years; median follow‐up period: 109 months) who had undergone radical surgery (including systemic lymphadenectomy) and subsequent adjuvant chemotherapy (patients with intermediate or high recurrence risk) from 2003 to 2015. Tissue microarrays were prepared from surgical specimens and classified using the conventional clinical risk classifier. Immunohistochemistry was used to detect mismatch repair proteins, L1 cell adhesion molecule, and p53. Direct sequencing was used to identify hotspot mutations in the polymerase‐epsilon gene. Forty‐five patients were identified as having high L1 cell adhesion molecule expression, 41 as low risk, 34 as mismatch repair‐deficient, 13 as polymerase‐epsilon gene‐mutated, five as having abnormal p53, and 46 as other. Patients were stratified into significantly different prognostic groups (p < 0.0001): favorable (low risk and polymerase‐epsilon gene‐mutated), intermediate (mismatch repair‐deficient and other), and unfavorable (high L1 cell adhesion molecule expression and abnormal p53) with 5‐year disease‐specific survival rates of 100%, 93.8%, and 75.1%, respectively (Kaplan–Meier method). The combination of conventional recurrent risk classification, sequencing for polymerase‐epsilon gene mutations and immunohistochemistry for L1 cell adhesion molecule, p53, and mismatch repair proteins can be used to determine the prognoses of patients with endometrial cancer.

Association of gene mutations with clinicopathologic features in patients with external auditory canal squamous cell carcinoma

BACKGROUND

External auditory canal squamous cell carcinoma (EACSCC) is a rare form of malignant tumor. Due to the extremely limited understanding of the genomic landscape in EACSCC, the association between gene mutations and clinicopathologic features remains unclear. This study aimed to explore somatic gene mutations associated with the clinicopathological features in patients with EACSCC, and to identify the candidate gene mutations for predicting survival outcome in EACSCC.

METHODS

Twenty-two tissue samples obtained from patients with EACSCC were analyzed for genetic mutations based on targeted next-generation sequencing and genetic expression based on IHC staining to investigate the driver of tumorigenesis and/or the candidates of genes for predicting clinical outcome in EACSCC.

RESULTS

Gene alterations were most frequently observed in TP53 (59.1%), followed by CREBBP (9.1%). TP53 mutations showed significant correlation with T classification (P = 0.027) and p53 expression phenotype (P < 0.001). The 5-year overall survival (OS) rates for EACSCC patients with TP53 mutations and wild-type TP53 were 45.0% and 75.0%, respectively. Multivariable analysis using the Cox proportional hazards model demonstrated that TP53 mutations were independent predictors of OS rates for EACSCC patients (P = 0.007).

CONCLUSION

This study has suggested that TP53 mutations have potential for use as a biomarker for identifying individuals at high risk of developing tumors and for predicting survival outcome in EACSCC. IHC staining for p53 might play a useful role as screening tool for detecting TP53 mutations in patients with EACSCC.

Clinical Relevance of Estrogen Reactivity in the Breast Cancer Microenvironment

Purpose

Estrogen signals play an important role in the phenotype of estrogen receptor-positive breast cancer. However, comprehensive analyses of the effect of responsiveness to estrogen signals on the tumor microenvironment and survival in large cohorts of primary breast cancer patients have been lacking. We aimed to test the hypothesis that estrogen reactivity affects gene expression and immune cell infiltration profiles in the tumor microenvironment and survival.

Methods

A total of 3,098 breast cancer cases were analyzed: 1,904 from the Molecular Taxonomy of Breast Cancer (METABRIC) cohort, 1,082 from The Cancer Genome Atlas (TCGA) cohort, and 112 from the Hokkaido University Hospital cohort. We divided the group into estrogen reactivity-high and estrogen reactivity-low groups utilizing the scores of ESTROGEN_RESPONSE_EARLY and ESTROGEN_RESPONSE_LATE in Gene Set Variation Analysis.

Results

Breast cancer with high estrogen reactivity was related to Myc targets, metabolism-related signaling, cell stress response, TGF-beta signaling, androgen response, and MTORC1 signaling gene sets in the tumor microenvironment. Low estrogen reactivity was related to immune-related proteins, IL2-STAT5 signaling, IL6-JAK-STAT3 signaling, KRAS signaling, cell cycle-related gene sets, and EMT. In addition, breast cancer with high levels of estrogen reactivity had low immune cytolytic activity and low levels of immunostimulatory cells. It also had low levels of stimulatory and inhibitory factors of the cancer immunity cycle. Patients with high estrogen reactivity were also associated with a better prognosis.

Conclusion

We demonstrated the relationship between estrogen reactivity and the profiles of immune cells and gene expression, as well as survival.

An investigator-initiated phase II trial of a PARP inhibitor niraparib monotherapy for patients with pre-treated, BRCA-mutated, unresectable/recurrent biliary tract, pancreatic, and other gastrointestinal cancers (NIR-B trial)

TPS4174

Background: Recent comprehensive genomic profiling tests have revealed therapeutic target molecules. However, because many targets are present in only a small fraction of patients, a large number of patients need to be screened for enrollment in a single study. In order to overcome this patient identification barrier, the SCRUM-Japan, nationwide large-scale genomic profiling platform, efficiently has been performed umbrella- and basket-type clinical trials. Among the platforms, we have reported that there are BRCA1/2-mutated patients in biliary tract, pancreatic, and other gastrointestinal cancers. Niraparib is an anticancer drug belonging to poly(ADP-ribose) polymerase (PARP) inhibitors. Niraparib has been shown to be selective for PARP1/2, to be more cytotoxic among other PARP inhibitor because of its PARP trapping activity. Methods: This is an investigator-initiated, multicenter, three-cohort phase 2 study. Main eligibility criteria are unresectable, advanced or recurrent biliary tract cancers (cohort A), pancreatic cancers (cohort B), and other gastrointestinal cancers (cohort C) with BRCA1/2 gene mutations identified by germline test or genomic profiling test with either circulating tumor DNA (ctDNA) or tumor tissue, refractory or intolerant to previous treatments, and adequate organ function. Primary endpoint is the investigator-assessed objective response rate in each cohort with a threshold-response rate of 10% and an expected response rate of 35%. Key secondary endpoints are progression-free survival, overall survival, disease control rate, duration of response, and safety. Patients with body weight of 77 kg or more and a platelet count of 150,000 /µL or more receive 300 mg of niraparib, and less than 77 kg or having a platelet count less than 150,000 /µL receive 200 mg of niraparib, orally once daily. Furthermore, pre-treatment tumor tissue and serial ctDNA will be collected and analyzed to investigate the resistance mechanisms and provide clinically meaningful biomarker which may be used for identifying and implementing treatment changes. The trial was initiated in January 2021 with enrollment being ongoing. Thirty-three out of planned 60 patients (cohort A/B/C; 25/25/10, respectively) have been enrolled as of December 2021. Funding: Takeda Pharmaceutical Co., Ltd. Clinical trial information: jRCT2011200023.

Versican Secreted by Cancer-Associated Fibroblasts is a Poor Prognostic Factor in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is highly recurrent. Cancer-associated fibroblasts (CAFs), a major component of the tumor microenvironment, promote malignancy; however, the mechanisms underlying their actions are obscure. We aimed to identify CAF-specific proteins in HCC and determine whether they could be potential therapeutic targets.

METHODS

Using comprehensive proteomic analysis of CAFs and noncancerous fibroblasts (NFs) primary-cultured from resected HCC specimens from the same patients, CAF-specific proteins were identified. Immunohistochemistry for versican (VCAN) was performed on cancerous tissues obtained from 239 patients with HCC. Conditioned medium from CAFs transfected with siRNA for VCAN was analyzed in vitro.

RESULTS

CAFs significantly promoted HCC cell proliferation, migration, and invasion (p < 0.01, 0.01, and 0.01, respectively) compared with NFs. VCAN was upregulated in CAFs, and its stromal level correlated with poor differentiation (p = 0.009) and positive vascular invasion (p = 0.003). Stromal VCAN level was also associated with significantly lower overall (p = 0.002) and relapse-free (p < 0.001) survival rates. It also independently predicted prognosis and recurrence. VCAN-knockdown CAFs significantly suppressed HCC cell migration and invasion compared with negative control.

CONCLUSIONS

VCAN secreted from CAFs promoted malignant transformation of HCC cells and has potential as a new therapeutic target in HCC.

Clinical Features of Pancreatic Neuroendocrine Microadenoma: A Single-Center Experience and Literature Review

OBJECTIVES

Pancreatic neuroendocrine microadenoma (NEMA) is a nonfunctioning neuroendocrine tumor of less than 5 mm. Most studies of NEMA were based on autopsies, and few reports have revealed the clinical frequency of NEMA. We investigated the clinicopathological features of NEMA.

METHODS

The pathological results of the pancreatic resection specimens of patients, older than 18 years, who underwent pancreatic resection at Hokkaido University Hospital between April 2008 and December 2020 were retrospectively reviewed. The NEMAs were re-examined in detail and examined by immunohistochemical staining.

RESULTS

Among 850 patients enrolled in this study, 24 NEMAs were identified in 12 patients (1.4%). Of the 12 patients, 2 patients had multiple endocrine neoplasia type 1, and the others had no hereditary disease, including 2 patients with multiple NEMAs. A difference in the number of NEMA was observed between patients with multiple endocrine neoplasia type 1 and sporadic NEMA. Intratumoral Ki-67 heterogeneity was correlated with the Ki-67 index. One grade 2 NEMA (Ki-67 index, 4.6%) was detected, but ATRX and DAXX labeling showed intact nuclear protein expression.

CONCLUSIONS

Multiple sporadic NEMAs and grade 2 NEMAs were observed, suggesting that NEMA may have malignant potential. Thus, NEMAs should be carefully monitored for lymph node metastasis and postoperative recurrence.

Precision cancer genome testing needs proficiency testing involving all stakeholders

To implement precision oncology, analytical validity as well as clinical validity and utility are important. However, proficiency testing (PT) to assess validity has not yet been systematically performed in Japan. To investigate the quality of next-generation sequencing (NGS) platforms and cancer genome testing prevalent in laboratories, we performed pilot PT using patient samples. We prepared genomic DNA from the cancer tissue and peripheral blood of 5 cancer patients and distributed these to 15 laboratories. Most participating laboratories successfully identified the pathogenic variants, except for two closely located KRAS variants and 25 bp delins in EGFR. Conversely, the EGFR L858R variant was successfully identified, and the allele frequency was similar for all the laboratories. A high DNA integrity number led to excellent depth and reliable NGS results. By conducting this pilot study using patient samples, we were able to obtain a glimpse of the current status of cancer genome testing at participating laboratories. To enhance domestic cancer genome testing, it is important to conduct local PT and to involve the parties concerned as organizers and participants.

Cyclin-dependent kinase 4 upregulation mediates acquired resistance of dabrafenib plus trametinib in BRAF V600E-mutated lung cancer

Background

Combination therapy with the B-Raf inhibitor, dabrafenib, and the MEK inhibitor, trametinib (DT) is commonly used to treat patients with B-Raf proto-oncogene, serine/threonine kinase V600E (BRAF V600E)-mutated non-small cell lung cancer (NSCLC). However, the mechanisms through which cancer develops DT resistance are unclear. Here, we investigated new mechanisms underlying acquired DT-resistant NSCLC with the BRAF V600E mutation.

Methods

We compared genomic signatures before and after DT treatment in patients with NSCLC.

Results

Two of four patients treated with DT developed carcinomatous pleuritis within 3 months. Target DNA sequencing and quantitative polymerase chain reaction (PCR) analyses revealed the increased expression level of cyclin-dependent kinase 4 (CDK4). We also found prominent protein expression of CDK4 after DT treatment. Induction of CDK4 expression in a cell line derived from a patient with the BRAF V600E mutation resulted in partial resistance to dabrafenib.

Conclusions

Our findings suggest a possible relationship between CDK4 upregulation and acquired resistance to DT therapy.

The Japanese Society of Pathology Practical Guidelines on the handling of pathological tissue samples for cancer genomic medicine

Clinical cancer genomic testing based on next‐generation sequencing can help select genotype‐matched therapy and provide diagnostic and prognostic information. Pathological tissue from malignant tumors obtained during routine practice are frequently used for genomic testing. This article is aimed to standardize the proper handling of pathological specimens in practice for genomic medicine based on the findings established in “Guidelines on the handling of pathological tissue samples for genomic medicine (in Japanese)” published by The Japanese Society of Pathology (JSP) in 2018. The two‐part practical guidelines are based on empirical data analyses; Part 1 describes the standard preanalytic operating procedures for tissue collection, processing, and storage of formalin‐fixed paraffin‐embedded (FFPE) samples, while Part 2 describes the assessment and selection of FFPE samples appropriate for genomic testing, typically conducted by a pathologist. The guidelines recommend that FFPE sample blocks be used within 3 years from preparation, and the tumor content should be ≥30% (minimum 20%). The empirical data were obtained from clinical studies performed by the JSP in collaboration with leading Japanese cancer genome research projects. The Japanese Ministry of Health, Labour, and Welfare (MHLW) recommended to comply with the JSP practical guidelines in implementing cancer genomic testing under the national health insurance system in over 200 MHLW‐designated core and cooperative cancer genome medicine hospitals in Japan.

Novel Prognostic Stratification Factor Based on the Pathological Profile of the Invasive Front in Colorectal Cancer

BACKGROUND/AIM

This study aimed to develop a new pathological finding, namely, invasion front grade and verify its clinical usefulness.

MATERIALS AND METHODS

We re-examined haematoxylin-eosin-stained specimens in 162 stage II-III colorectal cancer patients who underwent radical resection. We assessed the desmoplastic reaction, Klintrup grade, and poorly differentiated cluster. These three findings were combined to form the invasion front grade (good prognosis group; Grade A, poor prognosis group; Grade B), and its reproducibility and prognostic stratification ability were statistically analysed.

RESULTS

Invasion front grade was Grade A in 116 cases and Grade B in 46 cases, and its kappa coefficient was 0.81 for interobserver and 0.74 for intraobserver variability. The 3-year recurrence-free survival rates of Grade A and Grade B were 90.4% and 55.9%. Multivariate analysis showed that invasion front grade was an independent prognostic factor.

CONCLUSION

Invasion front grade is useful as a prognostic stratification factor for stage II-III colorectal cancer.

Clinical significance of comprehensive genomic profiling tests covered by public insurance in patients with advanced solid cancers in Hokkaido, Japan

BACKGROUND

Comprehensive cancer genomic profiling has been used recently for patients with advanced solid cancers. Two cancer genomic profiling tests for patients with no standard treatment are covered by Japanese public health insurance since June 2019.

METHODS

We prospectively analyzed data of 189 patients with solid cancers who underwent either of the two-cancer genomic profiling tests at Hokkaido University Hospital and its liaison hospitals and whose results were discussed in molecular tumor board at Hokkaido University Hospital between August 2019 and July 2020.

RESULTS

All 189 patients had appropriate results. Actionable gene alterations were identified in 93 patients (49%). Frequent mutations included PIK3CA (12%) mutation, BRCA1/2 alteration (7%), ERBB2 amplification (6%) and tumor mutation burden-High (4%). The median turnaround time from sample shipping to acquisition by the expert panel was 26 days. Although 115 patients (61%) were provided with information for genotype-matched therapies, only 21 (11%) received them. Notably, four of eight patients below the age of 20 years were provided information for genotype-matched therapies, and three received them. Their response rates and disease control rates were 29% and 67%, respectively. Most patients who did not undergo the genotype-matched therapies were provided information for only investigational drugs in phases I and II at distant clinical trial sites in central Japan. Twenty-six patients were informed of suspected germline findings, while 11 patients (42%) received genetic counseling.

CONCLUSIONS

The publicly reimbursed cancer genomic profilings may lead to the modest but favorable therapeutic efficacy of genotype-matched therapy for solid cancer patients with no standard therapy. However, poor access to genotype-matched therapy needs to be resolved.

Biglycan, tumor endothelial cell secreting proteoglycan, as possible biomarker for lung cancer

OBJECTIVES

In lung cancer, surgery remains the most curative treatment and limited resection is beneficial for patients with low cardiopulmonary function and low malignancy tumors. However, there are no biomarkers of low malignancy to select candidates for limited resection without compromising the outcome of treatments. Recently we identified biglycan (BGN) as a tumor endothelial cell (TEC) marker that is associated with tumor progression in various cancers. In this study, we analyzed the association between BGN expression in TECs in lung cancer and cancer progression in patients.

MATERIALS AND METHODS

First, we performed immunohistochemistry of BGN with resected lung tumor tissues of 155 patients who had undergone thoracic surgery and analyzed the correlation between BGN-positive vessel density in primary lung tumors and clinicopathological factors. Second, we measured the BGN levels in preoperative serum of other 46 patients with lung cancer by ELISA, and analyzed the correlation between BGN expression in tumor tissues and blood BGN levels.

RESULTS

High BGN expression in the TECs was significantly associated with T factor, and was a significant negative predictor. BGN levels in preoperative serum of 46 patients with lung cancer was significantly correlated with BGN expression in the TECs. Preoperative serum BGN level was significantly lower in healthy volunteers and less invasive adenocarcinoma than in invasive adenocarcinoma and other lung carcinomas. These results suggest that low BGN level in preoperative serum in patients with lung cancer might indicate low malignancy.

CONCLUSIONS

BGN can be a potential biomarker for lung cancer.

Mesothelin blockage by Amatuximab suppresses cell invasiveness, enhances gemcitabine sensitivity and regulates cancer cell stemness in mesothelin-positive pancreatic cancer cells

BACKGROUND

Mesothelin is a 40-kDa glycoprotein that is highly overexpressed in various types of cancers, however molecular mechanism of mesothelin has not been well-known. Amatuximab is a chimeric monoclonal IgG1/k antibody targeting mesothelin. We recently demonstrated that the combine therapy of Amatuximab and gemcitabine was effective for peritonitis of pancreatic cancer in mouse model.

METHODS

We discover the role and potential mechanism of mesothelin blockage by Amatuximab in human pancreatic cells both expressing high or low level of mesothelin in vitro experiment and peritonitis mouse model of pancreatic cancer.

RESULTS

Mesothelin blockage by Amatuximab lead to suppression of invasiveness and migration capacity in AsPC-1 and Capan-2 (high mesothelin expression) and reduce levels of pMET expression. The combination of Amatuximab and gemcitabine suppressed proliferation of AsPC-1 and Capan-2 more strongly than gemcitabine alone. These phenomena were not observed in Panc-1 and MIA Paca-2 (Mesothelin low expression). We previously demonstrated that Amatuximab reduced the peritoneal mass in mouse AsPC-1 peritonitis model and induced sherbet-like cancer cell aggregates, which were vanished by gemcitabine. In this study, we showed that the cancer stem cell related molecule such as ALDH1, CD44, c-MET, as well as proliferation related molecules, were suppressed in sherbet-like aggregates, but once sherbet-like aggregates attached to peritoneum, they expressed these molecules strongly without the morphological changes.

CONCLUSIONS

Our work suggested that Amatuximab inhibits the adhesion of cancer cells to peritoneum and suppresses the stemness and viability of those, that lead to enhance the sensitivity for gemcitabine.

Enhanced Angiogenesis in Salivary Duct Carcinoma Ex-Pleomorphic Adenoma

Salivary duct carcinoma (SDC) is morphologically similar to breast cancer, with HER2-overexpression reported. With regard to the pattern of disease onset, SDC can arise from de novo or carcinoma ex-pleomorphic adenoma (Ca-ex-PA). Recently, multiple molecular profiles of SDC as well as breast cancer have been reported, with significant differences in HER2 expression between Ca-ex-PA and de novo. We assessed the differences in gene expression between onset classifications. We conducted immunohistochemical analysis and HER2-DISH for 23 patients and classified SDCs into three subtypes as follows: “HER2-positive” (HER2+/any AR), “Luminal-AR” (HER2-/AR+), and “Basal-like” (HER2-/AR-). We assessed the expression levels of 84 functional genes for 19 patients by using a qRT-PCR array. Ten cases were classified as HER2-positive, seven cases as Luminal-AR, and six cases as Basal-like. The gene expression pattern was generally consistent with the corresponding immunostaining classification. The expression levels of VEGFA, ERBB2(HER2), IGF1R, RB1, and XBP1 were higher, while those of SLIT2 and PTEN were lower in Ca-ex-PA than in de novo. The functions of those genes were concentrated in angiogenesis and AKT/PI3K signaling pathway (Fisher’s test: p-value = 0.025 and 0.004, respectively). Multiple machine learning methods, OPLS-DA, LASSO, and RandomForest, also show that VEGFA can be a candidate for the characteristic differences between Ca-ex-PA and de novo. In conclusion, the AKT/PI3K signaling pathway leading to angiogenesis was hyper-activated in all SDCs, particularly in those classified into the Ca-ex-PAs. VEGFA was over-expressed significantly in the Ca-ex-PA, which can be a crucial factor in the malignant conversion to SDC.

A case of radio-insensitive SMARCA4-deficient thoracic undifferentiated carcinoma with severe right heart failure

SMARCA4-deficient thoracic sarcomatoid tumors were characterized by inactivating mutations of SMARCA4 and often found in the chest of young and middle-aged males with a smoking history. Recently, SMARCA4-deficient thoracic sarcomatoid tumors were reported to represent primarily smoking-associated undifferentiated/de-differentiated carcinomas rather than primary thoracic sarcomas. The main complication of this tumor is compression of the respiratory tract and/or blood vessels. A 39-year-old man presented with a 2-month history of fever and dyspnea. Computed tomography revealed a mediastinal tumor invading the right and left pulmonary arteries. Because of severe right heart failure, we considered him ineligible for bronchoscopy. We scheduled palliative irradiation with 40 Gy/20 Fr to improve hemodynamics and perform endobronchial ultrasound transbronchial needle aspiration later. However, irradiation was ineffective, and his general condition deteriorated quickly and he died after a 7-week hospitalization. An autopsy revealed that the diagnosis was SMARCA4-deficient thoracic undifferentiated carcinoma. It has been reported that this tumor is insensitive to radiotherapy and there were some cases which responded to an immune checkpoint inhibitor. Therefore, when caring for patients with mediastinal tumors that invade and compress the trachea and large vessels, it is important to consider this tumor as a differential diagnosis and try to make a pathological diagnosis as soon as possible.

A novel Tn antigen epitope-recognizing antibody for MUC1 predicts clinical outcome in patients with primary lung adenocarcinoma

Mucin 1 (MUC1) expression is upregulated in multiple types of cancer, including lung cancer. However, the conventional anti-MUC1 antibody is not useful for the differentiation of malignant lung tumors and benign lesions due to its limited specificity. Our previous study screened a novel epitope-defined antibody against cancer-associated sugar chain structures that specifically recognizes the MUC1 Tn antigen (MUC1-Tn ED Ab). In the present study, its potential utility as a diagnostic marker and therapeutic tool for lung adenocarcinoma (ADC) was examined. Immunohistochemical analysis of a lung ADC tissue microarray was performed using the MUC1-Tn ED Ab (clone SN-102), and the results were compared with those of another clone and commercially available MUC1 antibodies. The association between positive immunoreactivity of SN-102 and clinicopathologic factors was analyzed. Furthermore, the association between MUC1-Tn expression and epithelial-mesenchymal transition markers and radiological characteristics was analyzed. Moderate or high MUC1-Tn expression (MUC1-Tn-H) was observed in 138 (78.9%) of the 175 lung ADC cases. MUC1-Tn-H was associated with male sex, cigarette smoking, tumor extension, pleural invasion, and higher preoperative serum carcinoembryonic antigen and cytokeratin 19 fragment levels. Tumors with MUC1-Tn-H had higher consolidation/tumor ratios according to computed tomography and greater uptakes of ¹⁸F-fluorodeoxyglucose. A total of 46 (26.9%) of the tumors had mesenchymal features, and MUC1-Tn positivity was higher in the mesenchymal group than in the epithelial and intermediate groups (P<0.01 and P<0.01, respectively). Patients with tumors exhibiting MUC1-Tn-H had significantly shorter 5-year overall and disease-free survival times (P=0.011 and P<0.001, respectively). Additionally, MUC1-Tn-H was identified as an independent prognostic factor in multivariate analysis (P=0.024). MUC1-Tn is specific for lung cancer cells and can improve diagnostic capabilities. Additionally, it may be a potential therapeutic target in lung ADC.

Impact of DNA integrity on the success rate of tissue-based next-generation sequencing: Lessons from nationwide cancer genome screening project SCRUM-Japan GI-SCREEN

In the nationwide cancer genome screening project SCRUM-Japan GI-SCREEN, 2590 archival formalin-fixed paraffin-embedded (FFPE) tumor tissues from 19 institutions were analyzed with two tissue-based next-generation sequencing (NGS) panels at the Clinical Laboratory Improvement Amendments (CLIA)-certified College of American Pathologists (CAP)-accredited central laboratory. The Oncomine Cancer Research Panel (OCP; 143 genes) succeeded in producing validated results for only 68.3% of the samples (%OCP-success). CE-IVD (25 genes) succeeded in 45.9% of the OCP-failed samples, leading to an overall NGS success (%combined-success) rate as high as 82.9%. Among 2573 samples, the DNA-integrity (ΔCt )-high (ΔCt  < 4.4, n = 1253) samples showed significantly higher %OCP- and %combined-success rates (90.2% and 97.4%, respectively) than the DNA-integrity-intermediate (4.4 < ΔCt  < 6.3, n = 911; 68.9% and 88.7%) and DNA-integrity-low ones (ΔCt  > 6.3 or polymerase chain reaction-failed, n = 409; 5.6% and 24.7%). Other factors associated with NGS success included the FFPE-sample storage period (<4 years), the specimen type (surgical) and the primary tumor site (colorectal). Multivariable analysis revealed DNA integrity as the factor with the strongest independent association with NGS success, although it was suggested that other institution-specific factors contribute to the discordance of inter-institutional NGS success rates. Our results emphasize the importance of DNA quality in FFPE samples for NGS tests and the impact of DNA integrity on quality monitoring of pathology specimens for achieving successful NGS.

Adenomatous polyposis coli-binding protein end-binding 1 promotes hepatocellular carcinoma growth and metastasis

This study was performed to determine the clinical significance of adenomatous polyposis coli (APC)-binding protein end-binding 1 (EB1) in hepatocellular carcinoma (HCC) and to characterize its biochemical role in comparison with previous reports. We performed immunohistochemical staining to detect EB1 expression in tissues from 235 patients with HCC and investigated its correlations with clinicopathological features and prognosis. We also investigated the roles of EB1 in cell proliferation, migration, and tumorigenesis in vitro and in vivo by siRNA- and CRISPR/Cas9-mediated modulation of EB1 expression in human HCC cell lines. The results showed that EB1 expression was significantly correlated with several important factors associated with tumor malignancy, including histological differentiation, portal vein invasion status, and intrahepatic metastasis. Patients with high EB1 expression in HCC tissue had poorer overall survival and higher recurrence rates than patients with low EB1 expression. EB1 knockdown and knockout in HCC cells reduced cell proliferation, migration, and invasion in vitro and inhibited tumor growth in vivo. Further, genes encoding Dlk1, HAMP, and SLCO1B3 that were differentially expressed in association with EB1 were identified using RNA microarray analysis. In conclusion, elevated expression of EB1 promotes tumor growth and metastasis of HCC. EB1 may serve as a new biomarker for HCC, and genes coexpressed with EB1 may represent potential targets for therapy.

Multiplex gene-panel testing for lung cancer patients

The year 2019 was considered to be the first year of cancer genome medicine in Japan, with three gene-panel tests using next-generation sequencing (NGS) techniques being introduced into clinical practice. Among the three tests, the Oncomine CDx Target test was approved under the category of regular molecular testing for lung cancer, which meant that this test could be used to select patients for molecularly targeted drugs. Conversely, the other two tests, NCC OncoPanel and FoundationOne CDx, were assigned to be used under the National Cancer Genome Medicine Network, and implementation was restricted to patients for whom standard treatment was completed or expected to be completed. These NGS tests can detect a series of genetic alterations in individual tumors, which further promotes the development of therapeutic agents and elucidates molecular pathways. The NGS tests require appropriate tissue size and tumor cell content, which can be accessed only by pathologists. In this report, we review the current reimbursement schema in our national healthcare policy and the requirements of the specimens for NGS testing based on the recently published 'Guidance of Gene-panel Testing Using Next-Generation Sequencers for Lung Cancer', by the Japanese Society of Lung Cancer.

Japanese Society of Medical Oncology Clinical Guidelines: Molecular Testing for Colorectal Cancer Treatment, 4th edition

Molecular testing to select the appropriate targeted and standard of care therapies is essential for managing patients with colorectal cancer (CRC). The Japanese Society of Medical Oncology previously published clinical guidelines for molecular testing in CRC. In the third edition published in 2018, RAS and BRAF V600E mutations should be tested prior to first‐line chemotherapy to assess the benefit of anti–epidermal growth factor receptor (EGFR) antibody therapy in patients with unresectable CRC. Microsatellite instability (MSI) testing was recommended in patients with curatively resected stage II CRC because deficient mismatch repair is associated with low risk of recurrence. MSI testing was also recommended in patients with CRC suspected to be Lynch syndrome. The main aim of this fourth edition is to reflect recent advances in comprehensive genomic profiling (CGP) tests and liquid biopsy. Here, CGP tests performed on tumor tissues are strongly recommended to assess the benefit of molecular targeted drugs in patients with CRC. Circulating tumor DNA (ctDNA)‐based CGP tests are also proposed. ctDNA testing is recommended to determine the optimal treatment based on the risk of recurrence for curatively resected CRC and evaluate the suitability and monitor the therapeutic effects of anti–EGFR antibodies in patients with unresectable CRC. While both MSI testing and immunohistochemistry are strongly recommended to determine the indication of immune checkpoint inhibitors in patients with unresectable CRC, next‐generation sequencing‐based tests are weakly recommended because these tests have not been validated in clinical trials.

Association of Epstein-Barr virus with regression after withdrawal of immunosuppressive drugs and subsequent progression of iatrogenic immunodeficiency-associated lymphoproliferative disorders in patients with autoimmune diseases

Patients with autoimmune diseases (AIDs) may develop lymphoproliferative disorders (LPDs) during treatment with immunosuppressive agents (IS) such as methotrexate (MTX), biological agents, or tacrolimus. Some LPDs in patients with AIDs (AID-LPDs) regress after withdrawal of IS, and a high incidence of Epstein-Barr virus (EBV) positivity in such patients has been reported. To identify characteristics and factors predictive of the response to treatment and disease progression, we retrospectively analyzed clinical and histopathological data for 81 patients with AID-LPDs. Almost all of them (96%) had been treated with MTX. Diffuse large B cell lymphoma was the most common LPD type (61%) and seven patients (9%) had classical Hodgkin lymphoma (CHL). EBV was detected by in situ hybridization with an EBV-encoded small RNA (EBER) probe in 43% of the examined cases. In 59 patients, IS was discontinued as the initial treatment, resulting in regression of LPDs in 69% of them, and multivariate analysis showed that EBER positivity was an independent factor predictive of such regression (p = 0.022). Two-year progression-free survival (PFS) and overall survival for the patients overall were 63% and 83%, respectively. Poor PFS was associated with advanced stage (p = 0.024), worse performance status (PS, p = 0.031), CHL histology (p = 0.013), and reactivation of EBV-related antibodies (p = 0.029). In conclusion, EBV positivity demonstrated using an EBER probe is useful for prediction of successful regression after withdrawal of IS in patients with AID-LPDs. Patients with advanced stage disease, worse PS, CHL histology, or reactivation of EBV-related antibodies should be closely monitored after initial treatment.

Low expression of gamma-glutamyl transpeptidase 1 is an independent poor prognostic factor in ovarian clear cell carcinoma, in relation to up-regulation of immune suppressive genes and EMT-related genes

6042

Background: Ovarian clear cell carcinoma (OCCC) is a distinct entity from other epithelial ovarian cancers such as the most prevalent high-grade serous cancer (HGSC), and often exhibit less sensitivity to platinum-based chemotherapy. Several studies using cell lines have reported that glutathione (GSH) metabolism plays an important role in chemo-resistance of OCCC. Here, we aimed to correlate the prognosis of OCCC and the expression of gamma-glutamyltransferase 1 (GGT1), one of the key enzymes in GSH metabolism. Methods: We prepared a FFPE-tissue microarray, and analyzed 56 OCCC patients with the follow-up periods over 3 years. Expression level of GGT1 was evaluated by immunohistochemistry (IHC) using H-score (0-300), and was correlated with clinical outcomes. The prognostic significance was assessed by multivariate analysis using Cox regression model. To investigate the possible related pathways, we performed transcriptome analysis using Ion AmpliSeq Transcriptome Human Gene Expression Kit (Thermo Fisher Scientific) from the frozen tissue specimens collected from 33 ovarian cancer patients including 15 OCCC patients and 18 HGSC patients. Results: The OCCC patients were divided into two populations in the histogram of H-score in IHC staining, and the cut-off value was 90; 44 cases showed GGT1-high, and remaining 12 cases were GGT1-low. Follow-up periods, FIGO stage, and optimal surgery rate were not significantly different between two groups. However, platinum-resistant recurrent rate was significantly higher (42% vs. 14%, p=0.027), and overall survival (OS) was significantly shorter (5-year OS; 42% vs. 72%, p=0.0226) in GGT1-low OCCC. Multivariate analysis revealed that low expression of GGT1 was one of the independent poor prognostic factors as well as platinum-drug resistance. In enrichment analysis, the genes related to GSH metabolism, such as SLC3A1, GGT1, CSE, and GPX3 were up-regulated and positively correlated with HNF1B expression in OCCC. The expression level of GGT1 was inversely correlated with that of immune suppressive genes (TGF-b, IFNG, IL10, FOXP3, PD-L1, CTLA4) and epithelial-mesenchymal transition (EMT)-related genes (CDH2, VIM, TWIST1, ZEB1, ZEB2) in OCCC samples. Conclusions: Low expression of GGT1 is an independent poor prognostic factor probably in part due to suppression of tumor immunity and induction of EMT in OCCC.