IgG response to MHC class I epitope peptides is a quantitative predictive biomarker in the early course of treatment of colorectal cancer using therapeutic peptides

Cancer vaccines have been developed as a new therapeutic approach, however, their clinical benefit remains limited. We previously performed a phase II study for advanced colorectal cancer (CRC) using five human leukocyte antigen (HLA-A*24:02)-restricted peptides derived from kinase of the outer chloroplast membrane 1, translocase of outer mitochondrial membrane 34 (TOMM34), ring finger protein 43 (RNF43), vascular endothelial growth factor receptor 1 (VEGFR1) and VEGFR2. In the present study the relationship between overall survival (OS) and several biomarkers, including cytotoxic T lymphocyte (CTL) and immunoglobulin G (IgG) responses to these five peptides, was investigated. In 89 advanced CRC patients treated with a combination therapy consisting of these five peptides and oxaliplatin-based chemotherapy, plasma was collected before and after 3 months of vaccine administration. IgGs reactive to each of the five peptides were assessed using the multiplex bead suspension Luminex system. Antigen-specific T-cell responses were estimated by enzyme-linked immunoSpot assay. Plasma levels of TOMM34 IgG (P<0.001), RNF43 IgG (P<0.001) and VEGFR2 IgG (P<0.001) were significantly increased after vaccination and stronger VEGFR2 IgG responses correlated significantly with OS in HLA-matched patients (P=0.034). CTL responses to VEGFR1 and VEGFR2 were also significantly increased in the HLA-matched group (P=0.049 and P<0.001, respectively). However, increased CTL response did not correlate with OS. Multivariate analysis indicated that IgG responses to VEGFR2 were the most significant predictor for OS in the HLA-A*24:02-matched group (P=0.04). Our findings indicated that VEGFR2 IgG responses may be an important immunological biomarker in the early course of treatment for CRC patients treated with therapeutic epitope peptides.

Pharmacogenetic-based area-under-curve model to predict efficacy and adverse events from axitinib in individual patients with advanced renal cell carcinoma

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Background: Although titrated-dose axitinib offers a good objective response rate (ORR) for metastatic renal cell carcinoma (RCC), its optimal initial dose is unclear because its dosing regimen is based on a hypertensive reaction. We investigated whether axitinib pharmacogenetics were related to clinical efficacy/adverse events, and calculated a model to predict clinical efficacy and adverse events, using pharmacokinetic data based on gene polymorphisms in a phase 2 trial. Methods: We prospectively evaluated objective response and adverse events to establish a prediction model in 44 consecutive patients with advanced RCC, treated with axitinib between October 2013 and March 2017. Gene polymorphisms, including ABC transporters ( BCRP and MDR1) and UGT1A were analyzed by whole-exome sequencing, Sanger sequencing, and DNA chips. To construct the prediction model for area under curve (AUC), we used an exponential regression model with gene polymorphisms and dosage as covariates. To further validate this prediction model, we prospectively compared the calculated AUC in this model with actual AUCs in 13 additional consecutive patients. Results: Actual AUC was significantly correlated with the best ORR ( P = 0.0002), and adverse events (grade 2–3 hand–foot syndrome [ P = 0.0055]; grade 2 hypothyroidism [ P = 0.0381]); it was also significantly correlated with calculated AUC ( P < 0.0001). Calculated AUC was also significantly associated with best ORR ( P = 0.0044), grade 2–3 hand–foot syndrome ( P = 0.0191) and grade 2 hypothyroidism ( P = 0.0082). Surprisingly, hypertension was associated with neither ORR nor AUC. In the validation study, calculated AUC before axitinib treatment precisely predicted actual AUC ( P = 0.0079) in 13 additional consecutive patients. Conclusions: Our pharmacogenetics-based AUC model may offer a more benign method to determine optimal initial axitinib doses than hypertension, and could contribute to more precise treatment of individuals with advanced RCC. Clinical trial information: UMIN000011147.

TROY is a promising prognostic biomarker in patients with colorectal cancer

Tumor necrosis factor receptor superfamily member 19 (TROY) is involved in the Wnt/β-catenin signaling pathway and interacts with leucine-rich repeat containing G-protein-coupled receptor 5 (LGR5), which is a well-known biomarker of cancer stem cells and a prognostic marker of colorectal cancer (CRC). Because there have been no studies to evaluate the prognostic significance of TROY, we performed the present study to determine whether TROY can be a prognostic biomarker in CRC patients. We evaluated TROY expression levels in 100 CRC tissues by quantitative real-time PCR and investigated the association of TROY expression levels with clinicopathologic features. Cancer stage and TROY expression level were found to be independent prognostic factors of disease-free survival. Moreover, TROY overexpression was the sole independent prognostic factor of disease-free survival in patients with stage II and III CRC. These results suggest that analysis of TROY might help predict clinical outcome in patients with CRC. To support our findings, confirmatory studies using independent data sets are needed.

A randomized phase III clinical trial of sequential capecitabine or 5-FU plus bevacizumab (Cape/5-FU+Bmab) followed by Cape/5-FU plus oxaliplatin plus Bmab (CapeOX/mFOLFOX6+Bmab) versus combination CapeOX/mFOLFOX6+Bmab in advanced colorectal cancer: The C-cubed (C3) study

TPS872

Background: Less intensive regimens, focusing on survival and disease control, may be better first-line treatments in unresectable metastatic colorectal cancer (mCRC). Several randomized trials suggested that sequential cytotoxic agents in mCRC may improve overall survival compared with combination chemotherapy. This study investigated whether sequential treatment with Bmab-based first-line therapy with oxaliplatin has superior efficacy to combination treatment for unresectable mCRC. Methods: This study is a two-arm, multicenter, open-label, randomized phase III trial in Japan, comparing the efficacy and safety of sequential Cape/5-FU+Bmab with escalation to CapeOX/mFOLFOX6+Bmab versus combination CapeOX/mFOLFOX6+Bmab as the first-line treatment of mCRC. The primary endpoint is Time to failure of strategy (TFS). In the sequential arm (Arm A: oxaliplatin ‘wait-and-go’), treatment escalation from Cape/5-FU+Bmab to CapeOX/mFOLFOX6+Bmab is recommended for progressive disease. In the combination arm (Arm B: oxaliplatin ‘stop-and-go’), de-escalation from CapeOX/mFOLFOX6+Bmab to Cape/5-FU+Bmab is possible after 12 weeks of treatment. Re-escalation to CapeOX/mFOLFOX6+Bmab after progressive disease is considered only for patients who received de-escalation of oxaliplatin, not caused by oxaliplatin-associated toxicity, after 12 weeks of treatment. A target sample size of 304 evaluable patients is considered sufficient to detect a hazard ratio of 0.69 for the TFS of the sequential ‘wait-and-go’ approach compared with the combination ‘stop-and go’ approach with 80% power and a 2-sided significance level of 5%. From December 2014 to September 2016, 311 patients were enrolled across 81 centers in Japan. The follow-up period is until March 2018, and results are expected in 2019, and results are expected in 2019. Clinical trial information: 000015405.

Multicenter, phase II clinical trial of peptide vaccination with oral chemotherapy following curative resection for stage III colorectal cancer

The safety and immunological responsiveness of a peptide vaccine of ring finger protein 43 and 34-kDa translocase of the outer mitochondrial membrane combined with uracil-tegafur/leucovorin (UFT/LV) was previously demonstrated in metastatic colorectal cancer (CRC) in a phase I clinical trial. To clarify the survival benefit of a peptide vaccine combined with UFT/LV as adjuvant treatment, a phase II clinical trial was conducted involving patients with stage III CRC. All enrolled patients, whose human leukocyte antigen (HLA)-A status was double-blinded, were administered the same regime of a peptide vaccine and UFT/LV chemotherapy. The primary objective of the study was to compare relapse-free survival (RFS) in patients with HLA-A*2402 vs. those without HLA-A*2402. Secondary objectives included comparisons between the two groups regarding overall survival, safety, tolerability and peptide-specific activities of cytotoxic T lymphocytes (CTLs) as measured by the ELISPOT assay. Between December 2009 and December 2014, a total of 46 patients were enrolled to the present study. Three-year RFS was not significantly different between HLA-A*2402 matched and unmatched groups [67.8 vs. 73.6%, respectively; hazard ratio (HR)=1.254, 95% confidence interval (CI): 0.48–4.63; P=0.706]. Three-year RFS was significantly better in patients with positive CTL responses in the HLA-A*2402 matched group compared with those without (85.7 and 33.3%, respectively; HR=0.159, 95% CI: 0.023–0.697; P=0.011). In conclusion, vaccination-induced immune responses combined with UFT/LV were positively associated with survival benefit in patients with HLA-A*2402-positive stage III CRC. Further study is required to clarify whether vaccination-induced immune responses shortly following the initiation of therapy can predict the therapeutic effect and help develop a promising therapeutic strategy for patients with stage III CRC.

Stemness Is Enhanced in Gastric Cancer by a SET/PP2A/E2F1 Axis

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer-related deaths worldwide. Chemotherapies against gastric cancer often fail, with cancer recurrence due potentially to the persistence of cancer stem cells. This unique subpopulation of cells in tumors possesses the ability to self-renew and dedifferentiate. These cancer stem cells are critical for initiation, maintenance, metastasis, and relapse of cancers; however, the molecular mechanisms supporting cancer stemness remain largely unknown. Increased kinase and decreased phosphatase activity are hallmarks of oncogenic signaling. Protein phosphatase 2A (PP2A) functions as a tumor-suppressor enzyme, and elevated levels of SET/I2PP2A, an endogenous PP2A protein inhibitor, are correlated with poor prognosis of several human cancers. Here, it was determined that SET expression was elevated in tumor tissue in a gastric cancer mouse model system, and SET expression was positively correlated with poor survival of human gastric cancer patients. Mechanistically, SET knockdown decreased E2F1 levels and suppressed the stemness of cancer cell lines. Immunoprecipitations show SET associated with the PP2A-B56 complex, and the B56 subunit interacted with the E2F1 transcription factor. Treatment of gastric cancer cells with the SET-targeting drug OP449 increased PP2A activity, decreased E2F1 protein levels, and suppressed stemness of cancer cells. These data indicate that a SET/PP2A/E2F1 axis regulates cancer cell stemness and is a potential target for gastric cancer therapy.Implications: This study highlights the oncogenic role of SET/I2PP2A in gastric cancer and suggests that SET maintains cancer cell stemness by suppressing PP2A activity and stabilizing E2F1. Mol Cancer Res; 16(3); 554-63. ©2018 AACR.

[Three Cases of Obstructive Left-Sided Colon Cancer Resected by Laparoscopic Surgery]

We report 3 cases of obstructive left-sided colon cancer that could be treated with laparoscopic resection.Case 1: A 25- year-old man was given a diagnosis of colonic obstruction due to transverse colon cancer.Twenty -four days after decompression by a nasointestinal tube, we performed a laparoscopic partial colectomy.Case 2: A 75-year-old woman was given a diagnosis of colonic obstruction due to sigmoid colon.Forty -nine days after decompression by a laparoscopic transverse colostomy, we performed a laparoscopic sigmoidectomy.Case 3: A 48-year-old man was given a diagnosis of colonic obstruction due to sigmoid colon cancer.Twenty -two days after decompression by colonic stent, we performed a laparoscopic sigmoidectomy.In these 3 cases, decompression was sufficient when resecting the primary lesions, and the operations could be completed laparoscopically.Elective radical surgery was possible by resolution of oncologic emergency state.

High secreted protein acidic and rich in cysteine expression in peritumoral fibroblasts predicts better prognosis in patients with resectable gastric cancer

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix glycoprotein that may serve an important role in epithelial-mesenchymal transition. Recent studies have demonstrated that SPARC status is a prognostic indicator in various cancer types; however, its value remains unclear in gastric cancer (GC). In the present study, the localization and prognostic impact of SPARC expression were evaluated in patients with GC. Immunohistochemical analysis of SPARC expression was performed in 117 surgically resected GC specimens, and the localization of SPARC positive cells, as well as the rassociation between SPARC expression and clinicopathological characteristics were evaluated. High SPARC expression was observed in 47 cases; the glycoprotein was localized in the peritumoral fibroblasts, but was rarely observed in the cytoplasm of cancer cells. Heterogeneity of SPARC expression was observed in 52 cases. High stromal SPARC expression was identified to be an independent predictor of more favorable prognosis (overall survival and recurrence free survival) in all patients (P<0.001). On subgroup analysis, this association remained significant in patients who received adjuvant chemotherapy, but not in patients who did not (P<0.001). Stromal SPARC expression predicts better prognosis in GC patients who underwent curative resection; this appears to be associated with improved response to chemotherapy.

Expression levels of UL16 binding protein 1 and natural killer group 2 member D affect overall survival in patients with gastric cancer following gastrectomy

UL16 binding protein 1 (ULBP1) expressed on the tumor cell surface binds to the natural killer group 2 member D (NKG2D) receptor presenting on natural killer (NK), cluster of differentiation (CD)8⁺ T, and γ δ T cells. However, the roles of ULBP1 and NKG2D expression and associated immune responses in gastric cancer are unclear. The present study investigated the associations between ULBP1 and NKG2D expression and clinical outcomes in patients with gastric cancer. The levels of ULBP1 and NKG2D expression were examined in human gastric cancer cell lines and gastric cancer tissues from 98 patients who underwent surgery from 2004 to 2008. MKN-74 cells expressed ULBP1 with ULBP2, -5, or -6. NKG2D was expressed at a higher level following activation of T cells and NK cells. Among the tissue sections positive for NKG2D expression, 6 patients were positive for CD8 and CD56. In all tissues, NKG2D-expressing cells were typically aCD8⁺ T cells. Patients with NKG2D expression in tumors exhibited significantly longer overall survival (OS) compared with patients without NKG2D expression in tumors (P=0.0217). The longest OS was observed in patients positive for ULBP1 and NKG2D, whereas the shortest OS was observed in patients negative for ULBP1 and NKG2D. The interaction between ULBP1 and NKG2D may improve OS in patients with gastric cancer, and may have applications in immunotherapy for the induction of adaptive immunity in patients with cancer. Additionally, ULBP1 and NKG2D may be useful as prognostic biomarkers in gastric cancer.

[Two Cases of Laparoscopic Simultaneous Resection for Synchronous Liver Metastasis of Colon Cancer]

We report 2 cases of laparoscopic simultaneous resection for synchronous liver metastasis of colon cancer. Case 1: A 76- year-old woman was diagnosed with advanced cecum cancer(type 3)with synchronous liver metastasis(segment 5: 23mm), Laparoscopic ileocecal resection and partial liver resection were performed for 414 minutes, with 20 mL of blood loss. The patient was discharged 11 days after the operation. Case 2: A 78-year-old woman was diagnosed with advanced sigmoid colon cancer(type 2)with synchronous liver metastasis(segment 2: 70mm). Laparoscopic sigmoidectomy and extrahepatic resection were performed for 382 minutes, with 10 mL of blood loss. Portal vein thrombus(umbilicus)was recognized but relieved with warfarin. The patient was discharged 15 days after the operation. Simultaneous laparoscopic colon and hepatectomy for synchronous liver metastasis of colorectal cancer can be safely performed for selected indications.

[A Difficult Diagnostic Case of Pancreatic Acinar Cell Carcinoma]

The patient was a 46-year-old woman with left lower abdominal pain.Abdominal dynamic CT revealed a 40 mm, gradually- enhanced pancreatic head mass.The interior of the tumor was heterogeneous and partly low in density.Endoscopic ultrasonography showed a well-defined and heterogeneous tumor with an echoic area in the pancreatic head.Therefore, the cystic lesion with solid components was suspected to be a solid pseudopapillary neoplasm(SPN), considering the age of the patient.Subtotal stomach-preserving pancreaticoduodenectomy was performed.The postoperative course was uneventful, and she was discharged on the 13th day after surgery.Postoperative pathology confirmed a diagnosis of pancreatic acinar cell carcinoma.SPNs often show an image very similar to pancreatic acinar cell carcinoma and it is difficult to distinguish between the two only by imaging findings.Due to the divergence between clinical findings such as age and image findings, it was difficult to confirm a diagnosis of pancreatic acinar cell carcinoma in this case.

[A Case of Intrahepatic Cholangiocarcinoma with Ductal Plate Malformation Pattern]

A 56-year-old man with HCV infection was referred to our hospital for further evaluation and treatment of hepatic tumor. Abdominal enhanced computed tomography demonstrated an S8 hepatic tumor, about 15mm in maximal diameter. The tumor showed enhancement on the arterial phase and washout on equilibrium phase. EOB-MRI scan also showed the hepatic tumor with enhancement in the early phase and washout in the delayed phase. Liver function was normal. Serum AFP and PIVKA- II were normal and CEA and CA19-9 were elevated. However, no other tumor was detected by the colonoscopy, esophagogastroduodenoscopy and PET-CT. Under the diagnosis of HCC, partial hepatectomy was performed. Histologically, the tumor was composed of neoplastic glands with irregularly dilated lumen of adenocarcinoma, resembling ductal plate malformation(DPM). And Von Meyenburg complexes and foci of ordinary intrahepatic cholangiocarcinoma(ICC)were also found. ICC with this histologic features reported as a new subtype of ICCs.

[A Case of Colorectal Cancer with Peritoneal Dissemination and Liver Metastasis That Responded to Comprehensive Treatment by Chemotherapy and CRS plus HIPEC]

We report a case of colorectal cancer with peritoneal dissemination and liver metastasis that achieved R0 resection by preoperative chemotherapy and CRS plus HIPEC. A 33-year-old man presented with a complaint of abdominal bloating. After further examination, he was diagnosed with transverse colon cancer with peritoneal dissemination and liver metastasis. After 9 courses of preoperative XELOX plus cetuximab and 4 courses of preoperative XELIRI plus bevacizumab, he underwent transverse colon resection, peritoneal resection, and HIPEC(MMC 20mg/4,000mL physiological saline, 40mins). There was little histological evidence of peritoneal dissemination around the region of the primary tumor. Moreover, no tumor cells were found in other peritoneal disseminations or in the liver metastasis. As a result, he was able to undergo curative resection. Colorectal cancer with peritoneal dissemination still has a poor prognosis, but combination therapy with chemotherapy and CRS plus HIPEC is expected to improve prognosis.

[A Case of Conversion Surgery for Unresectable Colorectal Liver Metastases, Following Effective Combined Chemotherapy with Molecular Targeting Agents]

A 50-year-old man with complaints of epigastralgia, pyrexia, and malaise was diagnosed with sigmoid colon cancer, descending colon cancer, and unresectable colorectal liver metastases. Because the prognosticator was liver metastases, he went through chemotherapy(biweekly CapeOX plus cetuximab)as soon as possible. After 6 courses of this regimen, multiple liver metastases were markedly reduced in size(partial response[PR]), resulting in conversion therapy with complete resection. Recently, some reports showed that patients who had R0 resection after conversion chemotherapy could expect favorable long-term prognosis. It is important to select the appropriate first-line chemotherapy and the timing of the conversion resection.

miR-125b-1 and miR-378a are predictive biomarkers for the efficacy of vaccine treatment against colorectal cancer

Many clinical trials of peptide vaccines have been conducted. However, these vaccines have provided clinical benefits in only a small fraction of patients. The purpose of the present study was to explore microRNAs (miRNAs) as novel predictive biomarkers for the efficacy of vaccine treatment against colorectal cancer. First, we carried out microarray analysis of pretreatment cancer tissues in a phase I study, in which peptide vaccines alone were given. Candidate miRNAs were selected by comparison of the better prognosis group with the poorer prognosis group. Next, we conducted microarray analysis of cancer tissues in a phase II study, in which peptide vaccines combined with chemotherapy were given. Candidate miRNAs were further selected by a similar comparison of prognosis. Subsequently, we carried out reverse‐transcription PCR analysis of phase II cases, separating cancer tissues into cancer cells and stromal tissue using laser capture microdissection. Treatment effect in relation to overall survival (OS) and miRNA expression was analyzed. Three miRNA predictors were negatively associated with OS: miR‐125b‐1 in cancer cells (P = 0.040), and miR‐378a in both cancer cells (P = 0.009) and stromal cells (P < 0.001). Multivariate analysis showed that expression of miR‐378a in stromal cells was the best among the three predictors (HR, 2.730; 95% CI, 1.027–7.585; P = 0.044). In conclusion, miR‐125b‐1 and miR‐378a expression might be considered as novel biomarkers to predict the efficacy of vaccine treatment against colorectal cancer.

Local control of sphincter-preserving procedures and abdominoperineal resection for locally advanced low rectal cancer: Propensity score matched analysis

Sphincter‐preserving procedures (SPPs) for surgical treatment of low‐lying rectal tumors have advanced considerably. However, their oncological safety for locally advanced low rectal cancer compared with abdominoperineal resection (APR) is contentious. We retrospectively analyzed cohort data of 1500 consecutive patients who underwent elective resection for stage II‐III rectal cancer between 2010 and 2011. Patients with tumors 2‐5 cm from the anal verge and clinical stage T3‐4 were eligible. Primary outcome was 3‐year local recurrence rate, and confounding effects were minimized by propensity score matching. The study involved 794 patients (456 SPPs and 338 APR). Before matching, candidates for APR were more likely to have lower and advanced lesions, whereas SPPs were carried out more often following preoperative treatment, by laparoscopic approach, and at institutions with higher case volume. After matching, 398 patients (199 each for SPPs and APR) were included in the analysis sample. Postoperative morbidity was similar between the SPPs and APR groups (38% vs 39%; RR 0.98, 95% CI 0.77‐1.27). Margin involvement was present in eight patients in the SPPs group (one and seven at the distal and radial margins, respectively) and in 12 patients in the APR group. No difference in 3‐year local recurrence rate was noted between the two groups (11% vs 14%; HR 0.77, 95% CI 0.42‐1.41). In this observational study, comparability was ensured by adjusting for possible confounding factors. Our results suggest that SPPs and APR for locally advanced low rectal cancer have demonstrably equivalent oncological local control.

Abstract 1927: The significance of calreticulin in pancreatic cancer: a molecule highly expressed in pancreatic cancer stem-like cells

Cancer stem-like cells (CSLCs) in solid tumors are thought to be resistant to conventional chemotherapy or molecular targeting therapy and to contribute to cancer recurrence and metastasis. In this study, we aimed to identify a biomarker of pancreatic CSLCs (P-CSLCs). P-CSLC-enriched population was generated from pancreatic cancer cell lines using our previously reported method and its protein expression profile was compared with that of parental cells by two-dimensional electrophoresis and tandem mass spectrometry. The results indicated that a chaperone protein calreticulin (CRT) was significantly upregulated in P-CSLCs compared to parental cells. Flow cytometry analysis demonstrated that CRT was mostly localized to the surface of P-CSLCs and did not correlate with the levels of CD44v9, another P-CSLC biomarker. Furthermore, the side population in CRThigh/CD44v9low population is much higher than that in CRTlow/CD44v9high population. CRT expression was also assessed by immunohistochemistry in pancreatic cancer tissues (n = 80) obtained after radical resection and was found to be associated with patients’ clinicopathological features and disease outcomes in the Cox’s proportional hazard regression model. Multivariate analysis identified CRT as an independent prognostic factor for pancreatic cancer patients, along with age and post-operative therapy. Our results suggest that CRT can serve as a biomarker of P-CSLCs and a prognostic factor associated with poorer survival of pancreatic cancer patients. This novel biomarker can be useful for detecting P-CSLCs independently, which had been detectable by multiple surface markers like CD24, CD44 and ESA. We will present CSLCs properties of CRThigh population in P-CSLCs.

Citation Format: Satoshi Matsukuma, Kiyoshi Yoshimura, Atsunori Oga, Moeko Inoue, Takuya Fujimtoto, Atsuo Kuramasu, Masanori Fuse, Ryouichi Tsunedomi, Hidetoshi Eguchi, Hiroto Matsui, Shinsuke Kanekiyo, Yukio Tokumitsu, Shinobu Tomochika, Michihisa Iida, Yoshihiro Tokuhisa, Kazuhiko Sakamoto, Nobuaki Suzuki, Tomoko Furuya-Kondo, Hiroshi Itoh, Shigeru Takeda, Shigeru Yamamoto, Shigefumi Yoshino, Shoichi Hazama, Tomio Ueno, Hiroaki Nagano. The significance of calreticulin in pancreatic cancer: a molecule highly expressed in pancreatic cancer stem-like cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1927. doi:10.1158/1538-7445.AM2017-1927

Integrative analysis of genomic alterations in triple-negative breast cancer in association with homologous recombination deficiency

Triple-negative breast cancer (TNBC) cells do not express estrogen receptors, progesterone receptors, or human epidermal growth factor receptor 2. Currently, apart from poly ADP-ribose polymerase inhibitors, there are few effective therapeutic options for this type of cancer. Here, we present comprehensive characterization of the genetic alterations in TNBC performed by high coverage whole genome sequencing together with transcriptome and whole exome sequencing. Silencing of the BRCA1 gene impaired the homologous recombination pathway in a subset of TNBCs, which exhibited similar phenotypes to tumors with BRCA1 mutations; they harbored many structural variations (SVs) with relative enrichment for tandem duplication. Clonal analysis suggested that TP53 mutations and methylation of CpG dinucleotides in the BRCA1 promoter were early events of carcinogenesis. SVs were associated with driver oncogenic events such as amplification of MYC, NOTCH2, or NOTCH3 and affected tumor suppressor genes including RB1, PTEN, and KMT2C. Furthermore, we identified putative TGFA enhancer regions. Recurrent SVs that affected the TGFA enhancer region led to enhanced expression of the TGFA oncogene that encodes one of the high affinity ligands for epidermal growth factor receptor. We also identified a variety of oncogenes that could transform 3T3 mouse fibroblasts, suggesting that individual TNBC tumors may undergo a unique driver event that can be targetable. Thus, we revealed several features of TNBC with clinically important implications.

Cancer can result from genetic alterations, some of which can be good drug targets. To reveal genetic alterations that provide important information for the development of ideal therapeutic strategies for triple-negative breast cancer (TNBC), TNBC tumor samples were subjected to comprehensive genomic analyses. We identified novel recurrent structural variations associated with enhanced expression of the TGFA gene that encodes one of the high affinity ligands for epidermal growth factor receptor (EGFR). Although TGFA expression is known to be elevated in a subset of TNBC tumors, this is the first report of the mechanistic basis of this phenomenon. It is of particular importance considering that anti-EGFR agents are possible therapeutic options for TNBC patients. Our study also revealed several features associated with “BRCAness”, which is critical for identification of patients who may be responsive to platinum agents and/or poly ADP-ribose polymerase inhibitors. Thus, the data presented in this report may advance our understanding of the pathogenesis of TNBC.

Rapid and sensitive detection of UGT1A1 polymorphisms associated with irinotecan toxicity by a novel DNA microarray

Recent developments in the field of human genomics have greatly enhanced the potential for precision and personalized medicine. We have developed a novel DNA microarray, using a 3‐mm square chip coated with diamond‐like carbon to enhance the signal‐to‐background ratio, for use as an in vitro diagnostic tool in precision medicine. To verify the genotyping effectiveness of this newly developed DNA microarray we examined UDP‐glucuronosyltransferase 1A1 (UGT1A1) polymorphisms in DNA extracted from patients with metastatic colorectal cancer. It is established that the polymorphisms of UGT1A1*28 and UGT1A1*6 are significantly associated with severe toxicity induced by the anti‐cancer drug irinotecan. For each sample, the results obtained with the novel microarray platform were compared with those obtained using other, more established, methods, including direct sequencing and the Invader assay. The polymorphisms tested included a single nucleotide substitution (UGT1A1*6) and a TA‐repeat polymorphism (UGT1A1*28), both of which were detected simultaneously and accurately using our method. Moreover, our method required 1.5‐fold less time to assay and 20‐fold less sample than those required by the Invader assay. In summary, our newly developed DNA microarray is more practical than established methods, and is at least as accurate; this will increase the efficiency of polymorphism detection prior to diagnosis and the commencement of treatment, and can feasibly be applied in precision medicine.

miR-196b, miR-378a and miR-486 are predictive biomarkers for the efficacy of vaccine treatment in colorectal cancer

MicroRNAs (miRNAs/miRs) regulate the levels of transcripts and serve a critical function in the regulation of tumor microenvironments. Therefore, miRNA levels in cancer tissues are thought to be potential biomarkers for immunotherapy. From a phase I trial of a vaccine treatment using 5 human leukocyte antigen (HLA)-A*2402-restricted peptides (registration no. UMIN000004948), colorectal cancer (CRC) tissues were obtained from 8 patients and normal colorectal tissues from 5 patients via surgery. From a phase II trial using the same peptides (registration no. UMIN000001791), CRC tissues were obtained from 16 patients from the HLA-A*2402-matched group and 10 patients from the HLA-A*2402-unmatched group. These tissues were used for miRNA microarray analysis. As the first step, cancer tissues from the phase I study were used and 10 candidate miRNAs were selected by comparing the miRNA expression between two groups; one with improved prognosis and the other with poor prognosis. The miRNAs were subsequently validated using the cases enrolled in the phase II study. Significantly improved prognoses were identified in 16 patients in the HLA-A*2402-matched group with high expression of miR-196b-5p and low expression of miR-378a-3p and miR-486-5p. There was no difference in prognosis in the 10 patients in the HLA-A*2402-unmatched group. Therefore, high miR-196b expression and low miR-378a-3p and miR-486-5p expression were indicated as useful biomarkers for prediction of the efficacy of vaccine treatment for patients with metastatic CRC. In a planned phase III study, expression levels of these 3 miRNAs (miR-196b-5p, miR-378a-3p and miR-486-5p) may be useful biomarkers for assessing patients who are likely to have an improved outcome following vaccination.

A phase I study of novel multi-HLA-binding peptides and a new combination of immune adjuvants against solid tumors

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Background: Based on the exploratory analysis of our previous studies of peptide vaccine, we concluded that the combination of adjuvants hLAG-3Ig + Poly-ICLC is essential for controlling negative immune checkpoints and enhancing the induction of CTLs to overcome the traditional peptide studies. Another issue with peptide vaccines is human leukocyte antigen (HLA) restriction. Hence, we developed novel multi-HLA-binding peptides derived from the tumor antigens, HSP70 and GPC3, and confirmed the high expression in many types of cancer. Methods: For the identification of peptides, HSP70- and GPC3-derived peptides that have high binding affinity to each of HLA-A2402, 0201, and 0206 were selected as candidate peptides by a binding prediction system (NEC Corporation). We then identified priority candidate peptides by using a peptide-binding assay. Using peripheral mononuclear blood cells from cancer patients, CD8+ T lymphocytes were stimulated with the candidate peptides, and an enzyme-linked immunospot assay was performed. Finally, we identified HSP70- and GPC3-peptide. In this phase I study of a novel peptide cancer vaccine for metastatic solid cancer, primary objective was to evaluate its safety and toxicity. Secondary objective was to examine the immune and clinical response, and also to determine the recommendable dose. This study used a three-tiered dose-escalation strategy with 3 patients’ cohorts. In addition to the 3 scheduled cases, 3 more cases were added and 6 cases were enrolled at the recommended dose. Results: Twelve HLA-A*24:02-, 02:01-, and 02:06-matched patients (esophagus, 3; colon, 4; liver, 3; pancreas, 1; stomach, 1) were treated in this study. No severe adverse effects related to the treatment were encountered. Peptide-specific CTL induction with HSP70 and GPC3 was observed in 10 and 11 patients, respectively. We observed decreased tumor marker expression in 6 cases, and disease control was observed in f5 patients (4, 3, 8, 2, 2 months, respectively). Conclusions: The combination cancer vaccine therapy using multi-HLA-restricted peptides and hLAG-3Ig + Poly-ICLC was safe and effective for treating solid tumors; it therefore warrants further clinical studies. Clinical trial information: UMIN000020440.

Cetuximab strongly enhances immune cell infiltration into liver metastatic sites in colorectal cancer

Cetuximab has activity against colorectal cancers. Recent studies demonstrated that cetuximab induces antibody-dependent cell-mediated cytotoxicity via immune cells, and a new immune-related mechanism of inducing immunogenic cell death. This study aimed to evaluate the immune responses induced by cetuximab in tumor microenvironments at liver metastasis sites of metastatic colorectal cancer patients. We assessed immune cell infiltration in the liver metastatic sites of 53 colorectal cancer patients. These patients were divided into three groups according to the treatment before operation: chemotherapy with cetuximab, chemotherapy without cetuximab, and no chemotherapy. The inflammatory cells in the liver metastatic sites were assessed by hematoxylin-eosin staining, focusing on the invasive margin. The overall inflammatory reaction and number of lymphoid cells were assessed with a four-point scoring system. We then assessed immune cell infiltration (CD3, CD8 and CD56) in 15 liver metastatic sites. Hematoxylin-eosin staining demonstrated more inflammatory cells in the chemotherapy with cetuximab group than in the other groups (P < 0.001). Of note, inflammatory cells were found in intratumoral areas, and the destruction of cancer cell foci was observed in the chemotherapy with cetuximab group. Moreover, a higher infiltration of CD3+ (P = 0.003), CD8+ (P = 0.003) and CD56+ (P = 0.001) cells was observed in the chemotherapy with cetuximab group than in the other groups. These results suggest that cetuximab might have an immune-enhancing effect. As such, the immune-related mechanism of action of cetuximab may enhance the efficacy of combination therapy, such as chemotherapy and immunotherapy using therapeutic peptides.