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.

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.

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.

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

We undertook 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 carried out 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 of 10% or more 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 (interquartile range, 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% or more. Genomic alterations in FGF19 showed the strongest association with PFS with a borderline level of statistical significance of P = .00252 (Bonferroni-adjusted significance level is .0025). Genomic alterations in FGF4, MYEOV, CTTN, and ORAOV1 showed a marginal association with PFS (P < .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.

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/m(2) /day on days 1-14, and cisplatin at 75 mg/m(2) 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/m(2) /day). Considering treatment compliance, the recommended dose was determined to be S-1 60 mg/m(2) /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.

A non-randomized confirmatory study regarding selection of fertility-sparing surgery for patients with epithelial ovarian cancer: Japan Clinical Oncology Group Study (JCOG1203).

Fertility-sparing treatment has been accepted as a standard treatment for epithelial ovarian cancer in stage IA non-clear cell histology grade 1/grade 2. In order to expand an indication of fertility-sparing treatment, we have started a non-randomized confirmatory trial for stage IA clear cell histology and stage IC unilateral non-clear cell histology grade 1/grade 2. The protocol-defined fertility-sparing surgery is optimal staging laparotomy including unilateral salpingo-oophorectomy, omentectomy, peritoneal cytology and pelvic and para-aortic lymph node dissection or biopsy. After fertility-sparing surgery, four to six cycles of adjuvant chemotherapy with paclitaxel and carboplatin are administered. We plan to enroll 250 patients with an indication of fertility-sparing surgery, and then the primary analysis is to be conducted for 63 operated patients with pathologically confirmed stage IA clear cell histology and stage IC unilateral non-clear cell histology grade 1/grade 2. The primary endpoint is 5-year overall survival. Secondary endpoints are other survival endpoints and factors related to reproduction. This trial has been registered at the UMIN Clinical Trials Registry as UMIN000013380.

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.

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.

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.

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.

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.

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.

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.