Overexpression of the Wilms' tumor gene WT1 in de novo lung cancers

Expression of the Wilms' tumor gene WT1 in de novo lung cancer was examined using quantitative real-time RT-PCR and immunohistochemistry. Overexpression of the WT1 gene was detected by RT-PCR in 54/56 (96%) de novo non-small cell lung cancers examined and confirmed by detection of WT1 protein with an anti-WT1 antibody. Overexpression of the WT1 gene was also demonstrated in 5/6 (83%) de novo small cell lung cancers by immunohistochemistry. Furthermore, when the WT1 gene was examined for mutations by direct sequencing of genomic DNA in 7 lung cancers, no mutations were found. These results suggest that the nonmutated, wild-type WT1 gene plays an important role in tumorigenesis of de novo lung cancers and may provide us with the rationale for new therapeutic strategies for lung cancer targeting the WT1 gene and its products.

Overexpression of the Wilms' tumor gene W T1 in primary astrocytic tumors

Expression of the Wilms' tumor gene W T1 in primary astrocytic tumors was examined using a quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) or immunohistochemistry. Real-time RT-PCR showed that W T1 mRNA was expressed at various levels in all of the 25 astrocytic tumors examined. Immunohistochemical analysis showed that W T1 protein was expressed in 5 of 6 low-grade astrocytic tumors (grade I-II) and all of 18 high-grade ones (grade III-IV), and that expression levels of W T1 protein in high-grade tumors were significantly higher than those in low-grade ones. W T1 protein was not detected in the normal glial cells contained in the tumor specimens. Furthermore, treatment with W T1 antisense oligomers specifically inhibited growth of glioblastoma cell lines, U87-MG, A172, and T-98G. These results may indicate that the W T1 gene plays an important role in tumorigenesis of primary astrocytic tumors.

AML1-ETO rapidly induces acute myeloblastic leukemia in cooperation with the Wilms tumor gene, WT1

AML1-ETO, a chimeric gene frequently detected in acute myelogenous leukemia (AML), inhibits the differentiation of myeloid progenitors by suppressing genes associated with myeloid differentiation and increases the replating ability of clonogenic myeloid progenitors. However, AML1-ETO alone cannot induce AML and thus additional genetic events are required for the onset of AML. The Wilms tumor gene (WT1), which has been identified as the gene responsible for Wilms tumor, is expressed at high levels in almost all human leukemias. In this study, we have generated transgenic mice (WT1-Tg) that overexpress WT1 in hematopoietic cells to investigate the effects of WT1 on AML1-ETO-associated leukemogenesis. AML1-ETO-transduced bone marrow (BM) cells from WT1-Tg mice exhibited inhibition of myeloid differentiation at more immature stages and higher in vitro colony-forming ability compared with AML1-ETO-transduced BM cells from wild-type mice. Most importantly, all of the mice that received a transplant of AML1-ETO-transduced BM cells from the WT1-Tg mice rapidly developed AML. These results demonstrate that AML1-ETO may exert its leukemogenic function in cooperation with the expression of WT1.

Very low frequencies of human normal CD34+ haematopoietic progenitor cells express the Wilms' tumour gene WT1 at levels similar to those in leukaemia cells

The Wilms' tumour gene, WT1, is expressed at high levels in leukaemia cells and plays an important role in leukaemogenesis. WT1 is also expressed in human normal CD34+ bone marrow (BM) cells at about 100 times lower levels than in leukaemia cells. To identify and characterize WT1-expressing cells in CD34+ BM cells, they were sorted into single cells and analysed for WT1 expression using two kinds of single-cell reverse transcriptase polymerase chain reaction (RT-PCR) methods. Using the semiquantitative single-cell polyA-PCR + sequence-specific (SS)-PCR method, WT1 expression was detected in four (1.3%) out of 319 CD34+ BM single cells. To confirm the above results, a single-cell nested sequence-specific (NSS)-RT-PCR method that was less quantitative but more sensitive than the polyA-PCR + SS-PCR method was also performed, and WT1 expression was detected in 15 (1.1%) out of 1315 CD34+ BM single cells. In total, WT1 expression was found in 19 (1.2%) out of 1634 CD34+ BM single cells. No significant differences in the frequencies of WT1-expressing cells were found between CD34+CD38- and CD34+CD38+ BM single cells. Furthermore, WT1-expressing CD34+ BM single cells expressed WT1 at levels similar to those in K562 leukaemia single cells. Analysis of lineage-specific and cell cycle gene expression in WT1-expressing CD34+ BM single cells showed that the WT1 gene could be expressed in both uncommitted, dormant CD34+CD38- and lineage-committed, proliferating CD34+CD38+ BM cells. Our results could indicate that these WT1-expressing CD34+ BM cells were normal counterparts of leukaemia cells.

Phase I/II trial of chemoradiotherapy with concurrent S-1 and cisplatin for clinical stage II/III esophageal carcinoma (JCOG 0604)

We carried out a phase I/II trial of chemoradiotherapy concurrent with S-1 and cisplatin to determine the maximum tolerated dose and recommended dose and to evaluate the efficacy and safety of this treatment in patients with esophageal carcinoma. Thoracic esophageal cancer patients with clinical stage II/III disease, excluding T4, were eligible. Chemotherapy consisted of S-1 at a dose of 60–80 mg/m²/day on days 1–14, and cisplatin at 75 mg/m² on day 1, repeated twice every 4 weeks. Single daily radiation of 50.4 Gy was given in 28 fractions concurrently starting on day 1. Patients achieving an objective response after chemoradiotherapy underwent two additional cycles of chemotherapy. Patient accrual was terminated early due to slow enrolment after 44 patients were accrued. In the phase I part, two of six patients experienced dose-limiting toxicities at each level of S-1 (S-1 60 or 80 mg/m²/day). Considering treatment compliance, the recommended dose was determined to be S-1 60 mg/m²/day. The complete response rate, the primary endpoint of phase II, was 59.5% (22/37; 90% confidence interval, 44.6–73.1%; weighted threshold, 57.2%; P = 0.46 by the exact binomial test) on central review. In the phase II part, 3-year progression-free survival was 48.4%, with a 3-year overall survival of 61.9%. Grade 3 or 4 toxicity in phase II included leukopenia (57.9%), neutropenia (50%), hyponatremia (28.9%), anorexia (21.1%), anemia (18.4%), thrombocytopenia (18.4%), and febrile neutropenia (2.6%). No treatment-related deaths were observed. Although this combination showed acceptable toxicity and favorable 3-year survival, the study did not meet its primary endpoint. This trial was registered at the UMIN Clinical Trials Registry as UMIN000000710.

The lck promoter-driven expression of the Wilms tumor gene WT1 blocks intrathymic differentiation of T-lineage cells

In the thymi of WT1-transgenic (Tg) mice with the 17AA+/KTS- spliced form of the Wilms tumor gene WT1 driven by the lck promoter, the frequencies of CD4-CD8- double-negative (DN) thymocytes were significantly increased relative to those in normal littermates. Of the 4 subsets of CD4-CD8- DN thymocytes, the DN1 (CD44+CD25-) subset increased in both frequency and absolute cell number, whereas the DN2 (CD44+CD25+) and DN3 (CD44-CD25+) subsets decreased, indicating the blocking of thymocyte differentiation from the DN1 to the DN2 subsets. Furthermore, CD4-CD8+ T-cell receptor (TCR) -gammadelta T-cells increased in both frequency and absolute cell number in the spleen and peripheral blood of the WT1-Tg mice relative to those of normal littermates. The CD8 molecules of these CD4-CD8+ TCRgammadelta T-cells were CD8alphabeta, suggesting that they originated from the thymus. These results are the first direct evidence demonstrating that the WT1 gene is involved in the development and differentiation of T-lineage cells.

The Wilms' tumor gene WT1 is a common marker of progenitor cells in fetal liver

It is well known that the Wilms' tumor gene WT1 plays an important role in cell proliferation and differentiation, and in organ development. In this study, to examine the role of the WT1 gene in lineage determination, fetal liver cells from LacZ-transgenic mice, in which WT1 expression was marked by the expression of the LacZ gene driven by WT1 promoter, were FACS-sorted according to LacZ expression of high (LacZ(++)) or undetectable (LacZ(-)) levels, which paralleled endogenous WT1 expression levels. LacZ(++) fetal liver cells were enriched by hepatocyte and endothelial progenitor cells. These results indicated that WT1 expression is a common marker of both hepatocyte and endothelial progenitors. These results also implied a role of the WT1 gene in lineage determination.

A prognostic biomarker study in patients with clinical stage I esophageal squamous cell carcinoma: JCOG0502-A1

We conducted genomic analyses of Japanese patients with stage I esophageal squamous cell carcinoma (ESCC) to investigate the frequency of genomic alterations and the association with survival outcomes. Biomarker analysis was conducted for patients with clinical stage T1bN0M0 ESCC enrolled in JCOG0502 (UMIN000000551). Whole-exome sequencing (WES) was performed using DNA extracted from formalin-fixed, paraffin-embedded tissue of ESCC and normal tissue or blood sample. Single nucleotide variants (SNVs), insertions/deletions (indels), and copy number alterations (CNAs) were identified. We then evaluated the associations between each gene alteration with a frequency ≥10% and progression-free survival (PFS) using a Cox regression model. We controlled for family-wise errors at 0.05 using the Bonferroni method. Among the 379 patients who were enrolled in JCOG0502, 127 patients were successfully analyzed using WES. The median patient age was 63 years (IQR, 57-67 years), and 78.0% of the patients ultimately underwent surgery. The 3-year PFS probability was 76.3%. We detected 20 genes with SNVs, indels, or amplifications with a frequency of ≥10%. Genomic alterations in FGF19 showed the strongest association with PFS with a borderline level of statistical significance of p = 0.00252 (Bonferroni-adjusted significance level is 0.0025). Genomic alterations in FGF4, MYEOV, CTTN, and ORAOV1 showed a marginal association with PFS (p < 0.05). These genomic alterations were all CNAs at chromosome 11q13.3. We have identified new genomic alterations associated with the poor efficacy of ESCC (T1bN0M0). These findings open avenues for the development of new potential treatments for patients with ESCC.

Identification of a gene element essential for leukemia-specific expression of transgenes

Leukemia-specific promoters and enhancers for gene therapy had never been reported. Since the Wilms' tumor gene WT1 is overexpressed in almost all types of leukemia, WT1 is an ideal target of leukemia-specific therapy. To explore the possibility of gene therapy for leukemia using WT1 promoter and enhancer, their activities in several kinds of cells were analyzed by using the enhanced green fluorescent protein (EGFP) gene as a reporter. First, we identified the best combination (654P/EGFP/int3- enh/3'-enh vector) of the 654-bp WT1 promoter and the two WT1 enhancers located in intron 3 and at the 3' end of the WT1 gene for inducing EGFP expression in K562 cells, which endogenously expressed WT1. When this was transfected into WT1-expressing leukemia cells (K562, HEL), WT1-nonexpressing hematopoietic cells (Daudi, U937), and WT1-expressing nonhematopoietic cells (TYK-nu-CPr, SW480, 293 T), 19.8, 22.9, 1.47, 1.43, 4.50, 4.16, and 1.09 times EGFP expression was induced, respectively, compared to that by the promoter-less EGFP vector. These results showed that the 654P/EGFP/int3-enh/3'-enh vector specifically induced high levels of EGFP expression in WT1-expressing leukemia cells. 654P/int3- enh/3'-enh vector containing transgenes such as suicide genes might become useful tools for leukemia-specific gene therapy.

Phase I/II trial of chemoradiotherapy concurrent with S-1 and cisplatin in patients with clinical stage II/III esophageal carcinoma: Results of the Japan Clinical Oncology Group study JCOG 0604

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Background: We conducted a phase I/II trial of chemoradiotherapy (CRT) concurrent with S-1 and cisplatin to determine the maximum tolerated dose (MTD) and recommended dose (RD) and to evaluate the efficacy and safety in patients with esophageal carcinoma. Methods: Eligibility criteria included histologically proven squamous cell or adeno carcinoma of the thoracic esophagus, clinical stage II/III excluded T4, PS 0-1, age 20 to 75, and no prior treatment. Chemotherapy consisted of administration of S-1 60-80 mg/m2/day on days 1-14, and cisplatin at 75 mg/m2on day 1, repeated twice every 4 weeks. Single daily radiation of 1.8 Gy in 28 fractions (total 50.4Gy) was given concurrently starting on day 1. For patients achieving an objective response after CRT, two additional cycles of chemotherapy were administered. The phase I part adopted the 3+3 cohort design. Planned sample size of 75 patients was calculated based on the weighting of threshold values of CR rate according to the registered proportion of T1-2 and T3. Results: Patient accrual was terminated early due to slow enrollment after 44 eligible patients were accrued from May 2007 to Sep 2011. Patient backgrounds were: 40 males, with median age 62 years, PS 0/1 (39/5), squamous cell carcinoma / adenocarcinoma (43/1), T1/T2/T3 (14/8/22) and N0/N1 (7/36). In the phase I part, two of six patients experienced DLTs at each level of S-1 (S-1 60 or 80 mg/m2/day). Considering treatment compliance, RD was determined as S-1 60 mg/m2/day. The CR rate, primary endpoint of phase II, was 59.5% (22/37; 90%CI, 44.6-73.1%; the weighted threshold, 57.2%; p=0.46) on central review. In the phase II part, 3-year progression-free survival was 47.3% and 3-year overall survival was 61.9%. Grade 3 or 4 toxicity in phase II part included leukopenia (57.9%) neutropenia (50%), hyponatremia (28.9%), anorexia (21.1%), anemia (18.4%), thrombocytopenia (18.4%), and febrile neutropenia (2.6%). No treatment-related deaths were observed. Conclusions: Although CRT with S-1 plus cisplatin showed acceptable toxicity and favorable 3-year survival, this study did not meet its primary endpoint. Clinical trial information: 000000710.

Study protocol for JCOG1807C (DEEP OCEAN): a interventional prospective trial to evaluate the efficacy and safety of durvalumab before and after operation or durvalumab as maintenance therapy after chemoradiotherapy against superior sulcus non-small cell lung cancer

Background

Superior sulcus tumours (SSTs) are relatively uncommon and one of the most intractable lung cancers among non-small cell lung cancer (NSCLC). We planned a multicenter, single-arm confirmatory trial of new multidisciplinary treatment using immune-checkpoint inhibitor. The aim is to evaluate the safety and efficacy of new multidisciplinary treatment with perioperative durvalumab after chemoradiotherapy (CRT).

Methods

The primary endpoint is 3-year overall survival. Patients receive induction CRT with sequential two courses of durvalumab, followed by surgical resection for resectable SST. The regimen for CRT is two courses of cisplatin and S-1, and concurrent radiotherapy (66 Gy/33 Fr). After surgery, 22 courses of post-operative durvalumab therapy are administered. For unresectable SST, an additional 22 courses of durvalumab are administered after induction durvalumab.

Results

In two cases as a safety cohort, the safety of intervention treatment up to 30 days after surgery was examined, and there were no special safety signals. Patient enrollment has now resumed in the main cohort.

Conclusions

The results of this study may contribute to the establishment of a new standard of care for SST, which is an intractable NSCLC.

Utility of circulating tumour DNA for prognosis and prediction of therapeutic effect in locally recurrent rectal cancer: study protocol for a multi-institutional, prospective observational study (JCOG1801A1, CAP-LR study)

INTRODUCTION

In locally recurrent rectal cancer (LRRC), surgery is a standard treatment for resectable disease. However, short-term and long-term outcomes are unsatisfactory due to the invasive nature of surgical procedures and the high proportion of local recurrence. Consequently, the identification of reliable prognostic and predictive biomarkers to guide treatment decisions may improve outcomes. The presence of circulating tumour DNA (ctDNA) in plasma after surgery may signify the presence of minimal residual disease (MRD) in various cancers. Therefore, we have launched a multi-institutional prospective observational study of ctDNA for MRD detection in conjunction with JCOG1801, a randomised, controlled phase III trial evaluating the efficacy of preoperative chemoradiotherapy (pre-CRT) compared with up-front surgery for LRRC (jRCTs031190076, NCT04288999).

METHODS AND ANALYSIS

JCOG1801A1 is the first correlative study that assesses ctDNA in LRRC patients enrolled in JCOG1801. Patients randomised to up-front surgery will provide whole blood samples at three time points (prior to surgery, after surgery and after postoperative chemotherapy); those to pre-CRT will provide at five time points (prior to pre-CRT, after pre-CRT, prior to surgery, after surgery and after postoperative chemotherapy). Cell-free DNA will be extracted from plasma and analysed by Guardant Reveal, a tumour tissue-agnostic assay that assesses both genomic alterations and methylation patterns to determine the presence or absence of ctDNA. We will compare the prognosis and treatment response of patients according to their ctDNA status after surgery and at other time points.

ETHICS AND DISSEMINATION

The study protocol received approval from the Institutional Review Board of National Cancer Center Hospital East on behalf of the participating institutions in February 2023. The study is conducted in accordance with the precepts established in the Declaration of Helsinki and Ethical Guidelines for Medical and Biological Research Involving Human Subjects. Written informed consent will be obtained from all eligible patients prior to registration.

Overexpression of the Wilms' tumor gene WT1 in esophageal cancer

BACKGROUND

The Wilms' tumor gene WT1 is overexpressed in various kinds of solid cancers. However, it remains unclear whether WT1 is expressed in esophageal squamous cell carcinoma.

MATERIALS AND METHODS

Expression of the WT1 gene was examined by real-time RT-PCR in 12 esophageal squamous cell carcinoma (ESCC) and by immunohistochemistry in 9 of these 12 and another 29.

RESULTS

Real-time RT-PCR showed that the WT1 mRNA was overexpressed in all of the 12 ESCC examined Immunohistochemical analysis showed that the WT1 protein was overexpressed in ESCC cells in 36 (95%) of the 38 examined Furthermore, expression of the WT1 protein was examined in 20 esophageal squamous dysplasia. The WT1 protein was overexpressed in 5 (45%) out of 11 mild dysplasia and in 8 (89%) out of 9 moderate to severe dysplasia.

CONCLUSION

These results may indicate an important role of the WT1 gene in the tumorigenesis of ESCC.

Predictive and prognostic value of excision repair cross-complementing group 1 in patients with advanced gastric cancer

BACKGROUND

To define the optimal chemotherapy regimen for each patient we therefore used tissue from patients to identify molecular prognostic or predictive biomarkers.

METHODS

Endoscopic biopsy specimens from primary lesions and surgical specimens on a phase III trial in patients with unresectable advanced or recurrent gastric cancer treated with docetaxel with cisplatin plus S-1 (DCS) or cisplatin plus S-1 (CS), were collected. We measured the mRNA expression of ERCC1 and analyzed SNPs in GSTP1 and ERCC1.

RESULTS

Low ERCC1 expression was associated with favorable prognosis for overall survival, OS by multivariable analysis (P = 0.001). There were significant interactions between the two treatment arms of DCS and CS, and ERCC1 mRNA expression. In patients with low ERCC1 expression of a favorable prognosis, DCS therapy was inferior to CS (P = 0.046). In addition to GSTP1 rs1695 (HR 1.728), ERCC1 rs3212980, ERCC1 rs2298881, ERCC1 rs3212964 with high expression of ERCC1 mRNA were associated with significantly worse prognosis with regard to OS.

CONCLUSIONS

ERCC1 mRNA is an independent prognostic factor and predictive marker that can be used to guide the addition of docetaxel. The SNPs of ERCC1 and GSTP1 could be also prognostic or predictive factors.

Treatment-related deaths (TRD) in investigator-initiated cancer cooperative group trials: From the datasets of 44 studies (4,964 patients) by the Japan Clinical Oncology Group (JCOG)

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Background: The proportion of Serious Adverse Events (SAE) including TRDs has a critical impact on choosing a new standard therapy as well as the efficacy of treatment in clinical trials. The proportion of TRD (%TRD) has been reported in a single clinical trial, but an overall % TRD in plural clinical trials has merely been evaluated so far. Methods: The JCOG trials which met both of the following criteria were included in this analysis: i) started after 1995 by 2008, ii) primary analysis was completed. In JCOG, attribution of all reported SAE are classified by Data and Safety Monitoring Committee into 5 categories (definite, probable, possible, unlikely, not related) according to causality to protocol treatment, and the death with causality judged as definite, probable, or possible is defined as TRD. The total number of any deaths and TRD were counted in all included trials and the incidences (%) of TRD were calculated. The association between %TRD and the following trial profiles was evaluated: arm (standard vs. testing), phase, modality and median survival time of each arm. Results: In total, 44 JCOG trials (67 arms) with 4,964 patients were included in the analysis. The number of all deaths and TRD were 2,974 and 60. Thus, the overall %TRD for all enrolled patients was 1.2% (95%CI, 0.9–1.6%), and %TRD among all deaths was 2.0% (95%CI, 1.5–2.6%). Major results of the association between %TRD and trial profiles are shown in the table. The later phase trials showed the lower %TRD, and the trials with shorter MST tended to have higher %TRD. Conclusions: When the trial is in earlier phase and includes more advanced disease, the trial should be planned and performed more carefully about minimization of patient risk.

[Table: see text]

No significant financial relationships to disclose.

Lipidomic profiling of plasma from patients with multiple myeloma receiving bortezomib: an exploratory biomarker study of JCOG1105 (JCOG1105A1)

PURPOSE

A comprehensive analysis of metabolites (metabolomics) has been proposed as a new strategy for analyzing liquid biopsies and has been applied to identify biomarkers predicting clinical responses or adverse events associated with specific treatments. Here, we aimed to identify metabolites associated with bortezomib (Btz)-related toxicities and response to treatment in newly diagnosed multiple myeloma (MM).

METHODS

Fifty-four plasma samples from transplant-ineligible MM patients enrolled in a randomized phase II study comparing two less-intensive regimens of melphalan, prednisolone and Btz (MPB) were subjected to the lipidomic profiling analysis. The amount of each lipid metabolite in plasma obtained prior to MPB therapy was compared to toxicity grades and responses to MPB therapy.

RESULTS

High levels of 7 phospholipids (4 lysophosphatidylcholines and 3 phosphatidylcholines) were observed in cases with Btz-induced ≥ grade 2 peripheral neuropathy (BiPN) (n = 11). In addition, low levels of 3 fatty acids (FAs)-FA (18:2), FA (18:1), and FA (22:6)-were observed in patients who developed severe skin disorders ≥ grade 2 (n = 10). No metabolite significantly associated with treatment response was identified.

CONCLUSION

We conclude that levels of specific plasma lipid metabolites are associated with the severity of BiPN and skin disorders in patients with MM. These metabolites may serve as candidate biomarkers to predict Btz-induced toxicity in patients with MM before initiating Btz-containing therapy.

The genomic landscape and its prognostic significance for stage III colorectal cancer in Japan: An ancillary study of JCOG0910 trial—JCOG1506A1

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Background: To date, large-scale genomic sequencings of colorectal cancers (CRC) have been reported mainly from Western countries. However, ethnic diversities, differences by stage, and the prognostic impact of the genomic landscape in CRC remain poorly identified. Methods: The subjects were 534 patients (pts) with stage III CRC from the JCOG0910 study—a randomized phase-III trial conducted in Japan on 1564 pts to assess the efficacy of S-1 versus capecitabine as adjuvant chemotherapy. Targeted-capture sequencing of 171 potentially CRC-associated genes was performed on both normal tissue and tumor samples, and somatic single-nucleotide variants and insertion/deletions were determined. Tumors with MSIsensor scores > 7 and ultra-mutated tumors with POLE mutations were grouped as hypermutated tumors. Genes whose alterations were associated with recurrence-free survival (RFS) were evaluated using multivariable Cox regression models. Results: Of the 534 pts (right-sided: 184, left-sided: 350), 109 pts had recurrences or died during the study. Mutation frequencies were as follows: TP53, 75.3%; APC, 75.1%; KRAS, 43.6%; PIK3CA, 19.7%; FBXW7, 18.5%; SOX9, 11.8%; COL6A3, 8.2%; NOTCH3, 4.5%; NRAS, 4.1%; and RNF43, 3.7%. Thirty-one tumors were hypermutated (5.8%) (right: 14.1%, left: 1.4%). None of the 49 genes with mutation frequencies > 3% showed a significant association with RFS based on Bonferroni’s adjustment for multiple testing. The following modest associations were observed: mutant KRAS [HR, 1.66; p=0.011] and mutant RNF43 [HR, 2.17; p=0.055] had poorer RFS, whereas mutant COL6A3 [HR, 0.35; p=0.040] and mutant NOTCH3 [HR, 0.18; p=0.093] had better RFS. RFS tended to be better for hypermutated than for non-hypermutated tumors [HR, 0.53; p=0.229]. Conclusions: The overall mutation spectrum of our stage III CRC cohort was generally similar to that of the Cancer Genome Atlas (TCGA). However, the mutation frequencies of TP53, SOX9, and FBXW7 were higher, and the proportion of hypermutated tumors was lower. Multiple gene mutations seemed to impact RFS, indicating that tumor genomic profiling has a high potential to support precision medicine for pts with CRC.

Genomic landscape and its prognostic significance in stage III colorectal cancer: JCOG1506A1, an ancillary of JCOG0910

Large-scale genomic sequencing of colorectal cancers has been reported mainly for Western populations. Differences by stage and ethnicity in the genomic landscape and their prognostic impact remain poorly understood. We investigated 534 Japanese stage III colorectal cancer samples from the Phase III trial, JCOG0910. Targeted-capture sequencing of 171 potentially colorectal cancer-associated genes was performed, and somatic single-nucleotide variants and insertion-deletions were determined. Hypermutated tumors were defined as tumors with MSIsensor score >7 and ultra-mutated tumors with POLE mutations. Genes with alterations associated with relapse-free survival were analyzed using multivariable Cox regression models. In all patients (184 right-sided, 350 left-sided), mutation frequencies were TP53, 75.3%; APC, 75.1%; KRAS, 43.6%; PIK3CA, 19.7%; FBXW7, 18.5%; SOX9, 11.8%; COL6A3, 8.2%; NOTCH3, 4.5%; NRAS, 4.1%; and RNF43, 3.7%. Thirty-one tumors were hypermutated (5.8%; 14.1% right-sided, 1.4% left-sided). Modest associations were observed: poorer relapse-free survival was seen with mutant KRAS (hazard ratio 1.66; p = 0.011) and mutant RNF43 (2.17; p = 0.055), whereas better relapse-free survival was seen with mutant COL6A3 (0.35; p = 0.040) and mutant NOTCH3 (0.18; p = 0.093). Relapse-free survival tended to be better for hypermutated tumors (0.53; p = 0.229). In conclusion, the overall spectrum of mutations in our Japanese stage III colorectal cancer cohort was similar to that in Western populations, but the frequencies of mutation for TP53, SOX9, and FBXW7 were higher, and the proportion of hypermutated tumors was lower. Multiple gene mutations appeared to impact relapse-free survival, suggesting that tumor genomic profiling can support precision medicine for colorectal cancer.