Downregulation of SMOC1 is associated with progression of colorectal traditional serrated adenomas

BACKGROUND

Aberrant DNA methylation is prevalent in colorectal serrated lesions. We previously reported that the CpG island of SMOC1 is frequently methylated in traditional serrated adenomas (TSAs) and colorectal cancers (CRCs) but is rarely methylated in sessile serrated lesions (SSLs). In the present study, we aimed to further characterize the expression of SMOC1 in early colorectal lesions.

METHODS

SMOC1 expression was analyzed immunohistochemically in a series of colorectal tumors (n = 199) and adjacent normal colonic tissues (n = 112).

RESULTS

SMOC1 was abundantly expressed in normal colon and SSLs while it was significantly downregulated in TSAs, advanced adenomas and cancers. Mean immunohistochemistry scores were as follows: normal colon, 24.2; hyperplastic polyp (HP), 18.9; SSL, 23.8; SSL with dysplasia (SSLD)/SSL with early invasive cancer (EIC), 15.8; TSA, 5.4; TSA with high grade dysplasia (HGD)/EIC, 4.7; non-advanced adenoma, 21.4; advanced adenoma, 11.9; EIC, 10.9. Higher levels SMOC1 expression correlated positively with proximal colon locations and flat tumoral morphology, reflecting its abundant expression in SSLs. Among TSAs that contained both flat and protruding components, levels of SMOC1 expression were significantly lower in the protruding components.

CONCLUSION

Our results suggest that reduced expression of SMOC1 is associated with progression of TSAs and conventional adenomas and that SMOC1 expression may be a biomarker for diagnosis of serrated lesions and risk prediction in colorectal tumors.

Bob1 maintains T follicular helper cells for long-term humoral immunity

Humoral immunity is vital for host protection, yet aberrant antibody responses can trigger harmful inflammation and immune-related disorders. T follicular helper (Tfh) cells, central to humoral immunity, have garnered significant attention for unraveling immune mechanisms. This study shows the role of B-cell Oct-binding protein 1 (Bob1), a transcriptional coactivator, in Tfh cell regulation. Our investigation, utilizing conditional Bob1-deficient mice, suggests that Bob1 plays a critical role in modulating inducible T-cell costimulator expression and cellular respiration in Tfh cells. This regulation maintains the long-term functionality of Tfh cells, enabling their reactivation from central memory T cells to produce antibodies during recall responses. In a bronchial asthma model induced by house dust mite (HDM) inhalation, Bob1 is observed to enhance HDM-specific antibodies, including IgE, highlighting its pivotal function in Tfh cell regulation. Further exploration of Bob1-dependent mechanisms in Tfh cells holds promise for governing protective immunity and addressing immune-related disorders.

Quality of Palliative Radiation Therapy Assessed Using Quality Indicators: A Multicenter Survey

PURPOSE/OBJECTIVE(S)

Clinical practice is not always performed in accordance with guideline recommendations. Quality indicators (QIs) are valuable tools for evaluating the quality of healthcare systems. We sought to identify potential gaps between clinical practice and evidence using QIs previously developed using a modified Delphi method.

MATERIALS/METHODS

We used seven QIs (Table 1) to assess the quality of radiation therapy for bone (BoM) and brain metastases (BrM) at 29 centers; 13 (45%) were academic (12 university hospitals and 1 cancer center) and 16 (55%) were nonacademic hospitals. Compliance rate was calculated as the percentage of patients for whom recommended medical care was conducted. Random effects models were used to estimate pooled compliance rates. Mixed effects models with a Q test were used to compare compliance rates between academic and nonacademic centers.

RESULTS

The estimates of the compliance rates with 95% confidence intervals are presented in Table 1. For BoM-1, the compliance rate was higher in academic hospitals (100% [100-100%]) than in non-academic hospitals (96% [89-100%]) (P = 0.021). For BrM-3, the compliance rate was lower in academic hospitals (92% [81-99%]) than in nonacademic hospitals (100% [98-100%]) (P = 0.016).

CONCLUSION

A quality assessment based on these seven QIs is feasible. Overall, compliance rates were high; however, for BoM-3, the practice remains to be improved in some centers. Based on BoM-4 compliance rates, steroids are infrequently used concurrently with radiation therapy for malignant spinal cord compression. Extended fractionation for BoM was less frequently performed in academic than in nonacademic centers. The initiation of radiation therapy for brain metastases was more frequently delayed in academic than in nonacademic centers.

Health-Related Quality of Life at Five Years for a Randomized Trial of Tri-Modality Therapy with I-125 Brachytherapy, External Beam Radiation Therapy, and Short- vs. Long-Term Androgen Deprivation Therapy for High-Risk Localized Prostate Cancer (TRIP)

PURPOSE/OBJECTIVE(S)

To describe the patient-reported health-related quality of life (HR-QoL) outcomes at five years for a multicenter randomized trial of tri-modality therapy with iodine-125 brachytherapy, external beam radiation therapy (EBRT), and short- versus long-term androgen deprivation therapy (ADT) for high-risk localized prostate cancer (TRIP/TRIGU0907).

MATERIALS/METHODS

A total of 332 men with high-risk prostate cancer were randomized to either 6 months of ADT (n = 165) or 30 months of ADT (n = 167) in conjunction with combined modality radiation therapy. For the HR-QoL assessment, general HR-QoL and disease-specific HR-QoL were measured using the Japanese version of the Medical Outcomes Study 8-items Short-Form Health Survey (SF-8) and the Expanded Prostate Cancer Index Composite (EPIC). Patient-reported outcome questionnaires were filled out before ADT initiation, and five years after. Scores were reported as mean with the standard deviation. QoL end points were assessed as the change between pre and post treatment using paired student t-test. Changes in the International Prostate Symptom Scores (IPSS) score, including total score and subscores, were also evaluated. The study was powered according to the primary endpoint of biochemical progression free survival with HR-QoL as a secondary endpoint. In addition, recovery of testosterone level (300ng/dL or higher) was calculated as the cumulative incidence curve and compared between arms by log-rank test.

RESULTS

The cumulative incidence of biochemical progression, and salvage ADT treatment were not different between the arms. Mean domain scores at baseline were well balanced between the two arms in all HR-QoL. There were no differences in the SF-8 assessment and the total and subscore EPIC assessments between the arms. The average sexual function score was lower in short arm versus long arm; 16.24 versus 20.24 at baseline, but not different at five years, 9.96 versus 7.78 (p = 0.164). There were no significant differences between the arms for the total and subscore IPSS. Significantly higher percentage of patients, 71.7% in the short arm recovered to a normal testosterone level at 6 years after the initiation of ADT compared to 43.2% in long arm (p<0.0001).

CONCLUSION

At five years after ADT initiation, there were no significant differences in all score changes between the two arms with general HR-QoL and disease-specific HR-QoL. Most of HR-QoL returned to baseline level, and sexual function scores were low from baseline in this population. Two-years' adjuvant ADT did not affect HR-QoL at five years, although it significantly retarded testosterone recovery compared to 6 months of hormone therapy.

ACLP Activates Cancer-Associated Fibroblasts and Inhibits CD8+ T-Cell Infiltration in Oral Squamous Cell Carcinoma

We previously showed that upregulation of adipocyte enhancer-binding protein 1 (AEBP1) in vascular endothelial cells promotes tumor angiogenesis. In the present study, we aimed to clarify the role of stromal AEBP1/ACLP expression in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis showed that ACLP is abundantly expressed in cancer-associated fibroblasts (CAFs) in primary OSCC tissues and that upregulated expression of ACLP is associated with disease progression. Analysis using CAFs obtained from surgically resected OSCCs showed that the expression of AEBP1/ACLP in CAFs is upregulated by co-culture with OSCC cells or treatment with TGF-β1, suggesting cancer-cell-derived TGF-β1 induces AEBP1/ACLP in CAFs. Collagen gel contraction assays showed that ACLP contributes to the activation of CAFs. In addition, CAF-derived ACLP promotes migration, invasion, and in vivo tumor formation by OSCC cells. Notably, tumor stromal ACLP expression correlated positively with collagen expression and correlated inversely with CD8+ T cell infiltration into primary OSCC tumors. Boyden chamber assays suggested that ACLP in CAFs may attenuate CD8+ T cell migration. Our results suggest that stromal ACLP contributes to the development of OSCCs, and that ACLP is a potential therapeutic target.

Physical Properties and Cellular Metabolic Characteristics of 3D Spheroids Are Possible Definitive Indices for the Biological Nature of Cancer-Associated Fibroblasts

The current study's objective was to elucidate some currently unknown biological indicators to evaluate the biological nature of cancer-associated fibroblasts (CAFs). For this purpose, four different CAFs, CAFS1, CAFS2, SCC17F and MO-1000, were established using surgical specimens from oral squamous cell carcinomas (OSCC) with different clinical malignant stages (CAFS1 and CAFS2, T2N0M0, stage II; SCC17F and MO-1000, T4aN2bM0, stage IVA). Fibroblasts unrelated to cancer (non-CAFs) were also prepared and used as controls. Initially, confirmation that these four fibroblasts were indeed CAFs was obtained by their mRNA expression using positive and negative markers for the CAF or fibroblasts. To elucidate possible unknown biological indicators, these fibroblasts were subjected to a cellular metabolic analysis by a Seahorse bioanalyzer, in conjugation with 3D spheroid cultures of the cells and co-cultures with a pancreas ductal carcinoma cell line, MIA PaCa-2. The mitochondrial and glycolytic functions of human orbital fibroblasts (HOF) were nearly identical to those of Graves'-disease-related HOF (GOF). In contrast, the characteristics of the metabolic functions of these four CAFs were different from those of human conjunctival fibroblasts (HconF), a representative non-CAF. It is particularly noteworthy that CAFS1 and CAFS2 showed markedly reduced ratios for the rate of oxygen consumption to the extracellular acidification rate, suggesting that glycolysis was enhanced compared to mitochondrial respiration. Similarly, the physical aspects, their appearance and stiffness, of their 3D spheroids and fibroblasts that were induced effects based on the cellular metabolic functions of MIA PaCa-2 were also different between CAFs and non-CAFs, and their levels for CAFS1 or SCC17F were similar to those for CAFS2 or MO-1000 cells, respectively. The findings reported herein indicate that cellular metabolic functions and the physical characteristics of these types of 3D spheroids may be valuable and useful indicators for estimating potential biological diversity among various CAFs.

CXCL12 is expressed by skeletal muscle cells in tongue oral squamous cell carcinoma

BACKGROUND

The CXCL12/CXCR4 axis plays a pivotal role in the progression of various malignancies, including oral squamous cell carcinoma (OSCC). In this study, we aimed to clarify the biological and clinical significance of CXCL12 in the tumor microenvironment of OSCCs.

METHODS

Publicly available single-cell RNA-sequencing (RNA-seq) datasets were used to analyze CXCL12 expression in head and neck squamous cell carcinomas (HNSCC). Immunohistochemical analysis of CXCL12, α-smooth muscle antigen (α-SMA), fibroblast activation protein (FAP) and CD8 was performed in a series of 47 surgically resected primary tongue OSCCs. Human skeletal muscle cells were co-cultured with or without OSCC cells, after which CXCL12 expression was analyzed using quantitative reverse-transcription PCR.

RESULTS

Analysis of the RNA-seq data suggested CXCL12 is abundantly expressed in stromal cells within HNSCC tissue. Immunohistochemical analysis showed that in grade 1 primary OSCCs, CXCL12 is expressed in both tumor cells and muscle cells. By contrast, grade 3 tumors were characterized by disruption of muscle structure and reduced CXCL12 expression. Quantitative analysis of CXCL12-positive areas within tumors revealed that reduced CXCL12 expression correlated with poorer overall survival. Levels of CXCL12 expression tended to inversely correlate α-SMA expression and positively correlate with infiltration by CD8+ lymphocytes, though these relations did not reach statistical significance. CXCL12 was significantly upregulated in muscle cells co-cultured with OSCC cells.

CONCLUSION

Our results suggest that tongue OSCC cells activate CXCL12 expression in muscle cells, which may contribute to tumor progression. However, CXCL12 is reduced in advanced OSCCs due to muscle tissue destruction.

Serum amyloid A1 recruits neutrophils to the invasive front of T1 colorectal cancers

BACKGROUND AND AIM

The tumor microenvironment plays an essential role in the development and progression of colorectal cancer (CRC). We recently reported that crosstalk between CRC cells and tumor-associated macrophages (TAMs) via serum amyloid A1 (SAA1) promotes invasion by T1 CRCs. In the present study, we aimed to clarify the role of neutrophils in early CRCs.

METHODS

Immunohistochemical analysis of CD66b, chemokine CXC motif ligand 8 (CXCL8 or interleukin-8, IL-8) and matrix metalloproteinase-9 (MMP-9) was performed using primary T1 CRCs (n = 49). The HL-60 human promyelocytic leukemia cell line and THP-1 human monocytic leukemia cell line were used to obtain neutrophil-like and macrophage-like cells, respectively. Boyden chamber assays were used to analyze cell migration and invasion, and quantitative RT-PCR was used to analyze gene expression.

RESULTS

Immunohistochemical analysis revealed accumulation of neutrophils at the SAA1-positive invasive front of T1 CRCs. Experiments using HL-60 cells suggested that treatment with SAA1 induced neutrophil migration and expression of CXCL8 and MMP-9 in neutrophils and that neutrophils promote CRC cell migration and invasion. Immunohistochemistry confirmed accumulation of CXCL8- or MMP-9-positive neutrophils at the SAA1-positive invasive front of T1 CRCs. Moreover, co-culture experiments using CRC, THP-1 and HL-60 cells suggested that CRC cells activated by macrophages upregulate CXCL8 and MMP-9 in neutrophils.

CONCLUSIONS

Our results suggest that interplay between macrophages and CRC cells leads to recruitment of neutrophils to the invasive front of T1 CRCs and that SAA1 secreted by CRC cells activate neutrophils to promote invasion.

DLEU1 promotes oral squamous cell carcinoma progression by activating interferon-stimulated genes

Long noncoding RNAs (lncRNAs) are deeply involved in cancer development. We previously reported that DLEU1 (deleted in lymphocytic leukemia 1) is one of the lncRNAs overexpressed in oral squamous cell carcinoma (OSCC) cells, where it exhibits oncogenic activity. In the present study, we further clarified the molecular function of DLEU1 in the pathogenesis of OSCC. Chromatin immunoprecipitation-sequencing (ChIP-seq) analysis revealed that DLEU1 knockdown induced significant changes in the levels of histone H3 lysine 4 trimethylation (H3K4me3) and H3K27 acetylation (H3K27ac) in OSCC cells. Notably, DLEU1 knockdown suppressed levels of H3K4me3/ H3K27ac and expression of a number of interferon-stimulated genes (ISGs), including IFIT1, IFI6 and OAS1, while ectopic DLEU1 expression activated these genes. Western blot analysis and reporter assays suggested that DLEU1 upregulates ISGs through activation of JAK-STAT signaling in OSCC cells. Moreover, IFITM1, one of the ISGs induced by DLUE1, was frequently overexpressed in primary OSCC tumors, and its knockdown inhibited OSCC cell proliferation, migration and invasion. These findings suggest that DLEU1 exerts its oncogenic effects, at least in part, through activation of a series ISGs in OSCC cells.

Activated macrophages promote invasion by early colorectal cancer via an interleukin 1β-serum amyloid A1 axis

Submucosal invasion and lymph node metastasis are important issues affecting treatment options for early colorectal cancer (CRC). In this study, we aimed to unravel the molecular mechanism underlying the invasiveness of early CRCs. We performed RNA‐sequencing (RNA‐seq) with poorly differentiated components (PORs) and their normal counterparts isolated from T1 CRC tissues and detected significant upregulation of serum amyloid A1 (SAA1) in PORs. Immunohistochemical analysis revealed that SAA1 was specifically expressed in PORs at the invasive front of T1b CRCs. Upregulation of SAA1 in CRC cells promoted cell migration and invasion. Coculture experiments using CRC cell lines and THP‐1 cells suggested that interleukin 1β (IL‐1β) produced by macrophages induces SAA1 expression in CRC cells. Induction of SAA1 and promotion of CRC cell migration and invasion by macrophages were inhibited by blocking IL‐1β. These findings were supported by immunohistochemical analysis of primary T1 CRCs showing accumulation of M1‐like/M2‐like macrophages at SAA1‐positive invasive front regions. Moreover, SAA1 produced by CRC cells stimulated upregulation of matrix metalloproteinase‐9 in macrophages. Our data suggest that tumor‐associated macrophages at the invasive front of early CRCs promote cancer cell migration and invasion through induction of SAA1 and that SAA1 may be a predictive biomarker and a useful therapeutic target.

Upregulation of adipocyte enhancer-binding protein 1 in endothelial cells promotes tumor angiogenesis in colorectal cancer

Tumor angiogenesis is an important therapeutic target in colorectal cancer (CRC). We aimed to identify novel genes associated with angiogenesis in CRC. Using RNA sequencing analysis in normal and tumor endothelial cells (TECs) isolated from primary CRC tissues, we detected frequent upregulation of adipocyte enhancer‐binding protein 1 (AEBP1) in TECs. Immunohistochemical analysis revealed that AEBP1 is upregulated in TECs and stromal cells in CRC tissues. Quantitative RT‐PCR analysis showed that there is little or no AEBP1 expression in CRC cell lines, but that AEBP1 is well expressed in vascular endothelial cells. Levels of AEBP1 expression in Human umbilical vein endothelial cells (HUVECs) were upregulated by tumor conditioned medium derived from CRC cells or by direct coculture with CRC cells. Knockdown of AEBP1 suppressed proliferation, migration, and in vitro tube formation by HUVECs. In xenograft experiments, AEBP1 knockdown suppressed tumorigenesis and microvessel formation. Depletion of AEBP1 in HUVECs downregulated a series of genes associated with angiogenesis or endothelial function, including aquaporin 1 (AQP1) and periostin (POSTN), suggesting that AEBP1 might promote angiogenesis through regulation of those genes. These results suggest that upregulation of AEBP1 contributes to tumor angiogenesis in CRC, which makes AEBP1 a potentially useful therapeutic target.

Results of a multi-institutional, randomized, non-inferiority, phase III trial of accelerated fractionation versus standard fractionation in radiation therapy for T1-2N0M0 glottic cancer: Japan Clinical Oncology Group Study (JCOG0701)

Background

We assessed the non-inferiority of accelerated fractionation (AF) (2.4 Gy/fraction) compared with standard fractionation (SF) (2 Gy/fraction) regarding progression-free survival (PFS) in patients with T1-2N0M0 glottic cancer (GC).

Patients and methods

In this multi-institutional, randomized, phase III trial, patients were enrolled from 32 Japanese institutions. Key inclusion criteria were GC T1-2N0M0, age 20-80, Eastern Cooperative Oncology Group performance status of 0-1, and adequate organ function. Patients were randomly assigned to receive either SF of 66-70 Gy (33-35 fractions), or AF of 60-64.8 Gy (25-27 fractions). The primary end point was the proportion of 3-year PFS. The planned sample size was 360 with a non-inferiority margin of 5%.

Results

Between 2007 and 2013, 370 patients were randomized (184/186 to SF/AF). Three-year PFS was 79.9% (95% confidence interval [CI] 73.4-85.4) for SF and 81.7% (95% CI 75.4-87.0) for AF (difference 1.8%, 91% CI-5.1% to 8.8%; one-sided P = 0.047 > 0.045). The cumulative incidences of local failure at 3 years for SF/AF were 15.9%/10.3%. No significant difference was observed in 3-year overall survival (OS) between SF and AF. Grade 3 or 4 acute and late toxicities developed in 22 (12.4%)/21 (11.5%) and 2 (1.1%)/1 (0.5%) in the SF/AF arms.

Conclusion

Although the non-inferiority of AF was not confirmed statistically, the similar efficacy and toxicity of AF compared with SF, as well as the practical convenience of its fewer treatment sessions, suggest the potential of AF as a treatment option for early GC.

Clinical trials registration

UMIN Clinical Trial Registry, number UMIN000000819.

UHRF1 depletion and HDAC inhibition reactivate epigenetically silenced genes in colorectal cancer cells

BACKGROUND

Ubiquitin-like protein containing PHD and RING finger domains 1 (UHRF1) is a major regulator of epigenetic mechanisms and is overexpressed in various human malignancies. In this study, we examined the involvement of UHRF1 in aberrant DNA methylation and gene silencing in colorectal cancer (CRC).

RESULTS

CRC cell lines were transiently transfected with siRNAs targeting UHRF1, after which DNA methylation was analyzed using dot blots, bisulfite pyrosequencing, and Infinium HumanMethylation450 BeadChip assays. Gene expression was analyzed using RT-PCR and gene expression microarrays. Depletion of UHRF1 rapidly induced genome-wide DNA demethylation in CRC cells. Infinium BeadChip assays and bisulfite pyrosequencing revealed significant demethylation across entire genomic regions, including CpG islands, gene bodies, intergenic regions, and repetitive elements. Despite the substantial demethylation, however, UHRF1 depletion only minimally reversed CpG island hypermethylation-associated gene silencing. By contrast, the combination of UHRF1 depletion and histone deacetylase (HDAC) inhibition reactivated the silenced genes and strongly suppressed CRC cell proliferation. The combination of UHRF1 depletion and HDAC inhibition also induced marked changes in the gene expression profiles such that cell cycle-related genes were strikingly downregulated.

CONCLUSIONS

Our results suggest that (i) maintenance of DNA methylation in CRC cells is highly dependent on UHRF1; (ii) UHRF1 depletion rapidly induces DNA demethylation, though it is insufficient to fully reactivate the silenced genes; and (iii) dual targeting of UHRF1 and HDAC may be an effective new therapeutic strategy.

Surface microstructures are associated with mutational intratumoral heterogeneity in colorectal tumors

BACKGROUND

Recent studies revealed that colorectal tumors are composed of genetically diverse subclones. We aimed to clarify whether the surface microstructures of colorectal tumors are associated with genetic intratumoral heterogeneity (ITH).

METHODS

The surface microstructures (pit patterns) of colorectal tumors were observed using magnifying endoscopy, and biopsy specimens were obtained from respective areas when tumors exhibited multiple pit patterns. A total of 711 specimens from 477 colorectal tumors were analyzed for BRAF, KRAS and TP53 mutations using pyrosequencing and direct sequencing. A panel of cancer-related genes was analyzed through targeted sequencing in 7 tumors.

RESULTS

Colorectal tumors with multiple pit patterns exhibited more advanced pit patterns and higher frequencies of KRAS and/or TP53 mutations than tumors with a single pit pattern. In tumors with multiple pit patterns, mutations were observed as public (common to all areas) or private (specific to certain areas), and private KRAS and/or TP53 mutations were often variable and unrelated to the pit pattern grade. Notably, invasive CRCs frequently exhibited public TP53 mutations, even in adenomatous areas, which is indicative of their early malignant potential. Targeted sequencing revealed additional public and private mutations in tumors with multiple pit patterns, indicating their single clonal origin.

CONCLUSIONS

Our results suggest intratumoral pit pattern variation does not simply reflect the process of colorectal tumor evolution, but instead represents genetically diverse subclones, and this diversity may be associated with malignant potential.

Subtypes of the Type II Pit Pattern Reflect Distinct Molecular Subclasses in the Serrated Neoplastic Pathway

BACKGROUND

Colorectal serrated lesions (SLs) are important premalignant lesions whose clinical and biological features are not fully understood.

AIMS

We aimed to establish accurate colonoscopic diagnosis and treatment of SLs through evaluation of associations among the morphological, pathological, and molecular characteristics of SLs.

METHODS

A total of 388 premalignant and 18 malignant colorectal lesions were studied. Using magnifying colonoscopy, microsurface structures were assessed based on Kudo's pit pattern classification system, and the Type II pit pattern was subcategorized into classical Type II, Type II-Open (Type II-O) and Type II-Long (Type II-L). BRAF/KRAS mutations and DNA methylation of CpG island methylator phenotype (CIMP) markers (MINT1, - 2, - 12, - 31, p16, and MLH1) were analyzed through pyrosequencing.

RESULTS

Type II-O was tightly associated with sessile serrated adenoma/polyps (SSA/Ps) with BRAF mutation and CIMP-high. Most lesions with simple Type II or Type II-L were hyperplastic polyps, while mixtures of Type II or Type II-L plus more advanced pit patterns (III/IV) were characteristic of traditional serrated adenomas (TSAs). Type II-positive TSAs frequently exhibited BRAF mutation and CIMP-low, while Type II-L-positive TSAs were tightly associated with KRAS mutation and CIMP-low. Analysis of lesions containing both premalignant and cancerous components suggested Type II-L-positive TSAs may develop into KRAS-mutated/CIMP-low/microsatellite stable cancers, while Type II-O-positive SSA/Ps develop into BRAF-mutated/CIMP-high/microsatellite unstable cancers.

CONCLUSIONS

These results suggest that Type II subtypes reflect distinct molecular subclasses in the serrated neoplasia pathway and that they could be useful hallmarks for identifying SLs at high risk of developing into CRC.

Epigenetic silencing of SMOC1 in traditional serrated adenoma and colorectal cancer

Colorectal sessile serrated adenoma/polyps (SSA/Ps) are well-known precursors of colorectal cancer (CRC) characterized by BRAF mutation and microsatellite instability. By contrast, the molecular characteristics of traditional serrated adenoma (TSAs) are not fully understood. We analyzed genome-wide DNA methylation in TSAs having both protruding and flat components. We identified 11 genes, including SMOC1, methylation of which progressively increased during the development of TSAs. SMOC1 was prevalently methylated in TSAs, but was rarely methylated in SSA/Ps (p < 0.001). RT-PCR and immunohistochemistry revealed that SMOC1 was expressed in normal colon and SSA/Ps, but its expression was decreased in TSAs. Ectopic expression of SMOC1 suppressed proliferation, colony formation and in vivo tumor formation by CRC cells. Analysis of colorectal lesions (n = 847) revealed that SMOC1 is frequently methylated in TSAs, high-grade adenomas and CRCs. Among these, SMOC1 methylation was strongly associated with KRAS mutation and CpG island methylator phenotype (CIMP)-low. These results demonstrate that epigenetic silencing of SMOC1 is associated with TSA development but is rarely observed in SSA/Ps. SMOC1 expression could thus be a diagnostic marker of serrated lesions, and SMOC1 methylation could play a role in neoplastic pathways in TSAs and conventional adenomas.

Abstract 3385: Identification of tumor endothelium-related genes in colorectal cancer

Background and Aims:

Angiogenesis is a hallmark of cancer development that has been considered an attractive therapeutic target. In this study, we aimed to unravel the molecular mechanism of tumor angiogenesis in colorectal cancer (CRC).

Materials and Methods:

We isolated endothelial and epithelial cells from surgically resected 14 human CRC tissues by using antibodies against endothelial (CD146) and epithelial markers (EpCAM). RNA sequencing was carried out using 3 pairs of normal and tumor endothelial cells. Expression of the genes was validated using quantitative RT-PCR, immunohistochemistry. Functions of a selected gene were carried analyzed by tumor conditioned medium (TCM) experiments, tube formation assay, gene expression microarray and cell cycle analysis.

Results:

Through RNA-seq analysis, we identified 18 genes, which were upregulated in the endothelial cells isolated from CRC tissues. We further validated the results by performing quantitative RT-PCR and immunohistochemical analysis in a larger series of clinical samples, and identified gene A as a novel candidate of the tumor endothelium-related gene. Expression of gene A was also upregulated in human umbilical vein endothelial cells (HUVECs) treated with TCM obtained from CRC cell lines. Knockdown of gene A in HUVECs suppressed in vitro tube formation and induced G1 cell cycle arrest. Microarray analysis revealed that gene A knockdown induced expression changes of approximately 300 genes in HUVECs, and gene ontology analysis showed that genes related to cell cycle or cell division were significantly enriched in the affected genes. To confirm our findings in vivo, we co-transplanted CRC cells with HUVECs into nude mice. We found that gene A knockdown in HUVECs resulted in reduced micro vessel formations in the xenograft tissues.

Conclusion:

We identified elevated expression of gene A in tumor endothelial cells of primary colorectal cancer tissues. Our results suggest that gene A may play an important role in the angiogenesis in colorectal cancer, and that it could be a potential therapeutic target.

Citation Format: Akira Yorozu, Eiichiro Yamamoto, Reo Maruyama, Masahiro Kai, Toshihiko Nishidate, Tomohisa Furuhata, Tamotsu Sugai, Hiromu Suzuki. Identification of tumor endothelium-related genes in colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3385.

Carcinoma of the hard palate treated with radiotherapy: a retrospective review of 31 cases

There are few studies reporting the results of radical radiotherapy for carcinoma of the hard palate. We have examined our results of patients treated within a single institution, and assessed survival, local control and morbidity. A retrospective analysis was made on 31 patients with hard palate carcinoma treated with external beam radiotherapy at the Christie Hospital between 1990 and 1997. Twenty-six patients received radiotherapy alone and five were treated for post-operative positive surgical margins. The 5-year actuarial survival rate was 55%. The actuarial 5-year local control rate was 53%, rising up to 69% after salvage surgery. Survival was 48% for squamous cell carcinomas and 63% for salivary gland carcinomas, the difference was not significant. The only significant predictor of local control was T-stage, with 80% 5-year local control of T1-2 lesions and 24% control of T3-4 lesions. N-stage was the only significant factor predicting for survival. Radiation necrosis occurred in one patient. Radical radiotherapy for carcinoma of the hard palate is safe and well tolerated. It is an effective treatment for both squamous cell carcinoma and salivary gland carcinoma.

High-dose-rate brachytherapy boost following concurrent chemoradiotherapy for esophageal carcinoma

PURPOSE

To assess the efficacy, toxicity, and the optimum dose of high-dose-rate brachytherapy following chemoradiotherapy (CRT) compared with a historical group of patients treated with a combination of external beam and brachytherapy (RT alone).

METHODS AND MATERIALS

Fifty-three patients with localized esophageal cancer received concurrent chemoradiotherapy followed by brachytherapy. The chemotherapy regimen was a combination of cisplatin 60 mg/m2 on day 1 and fluorouracil 600 mg/m2 continuous infusion from days 1-4 during the first and last week of external irradiation. Radiotherapy consisted of external irradiation to a total dose of 40-61 Gy (median 50 Gy) and brachytherapy to 8-24 Gy (median 16 Gy) in 2-4 fractions.

RESULTS

Acute toxicity was well tolerated. A fistula occurred in one patient 1 week after completion of external irradiation. Local control was achieved in 32/53 (60%) compared with 42% of the RT group (p = 0.029). Local control rates of the CRT group were significantly better than those of the RT group in Stages II and III. Late toxicity (esophageal ulceration and strictures) occurred in 18 (34%) of the CRT group compared with 12% in the RT group (p = 0.013). Severe late toxicity (RTOG/EORTC criteria Grade 3-4) occurred in six patients (15%) whose chemotherapy was followed by 16-24 Gy via brachytherapy compared with 2.5% in the RT group (p = 0.010).

CONCLUSION

Combined chemoradiotherapy and brachytherapy boost achieved better local control than radiotherapy alone. However, a high level of severe late toxicity was observed especially with 16-24 Gy via brachytherapy.

Analysis of 57 nonagenarian cancer patients treated by radical radiotherapy: a survey of eight institutions

BACKGROUND

As the human society grows more aged, it is considered important to elucidate factors essential in applying radical radiotherapy (RT) to the elderly, with ages as high as 90 years and greater.

METHODS

A retrospective survey was conducted for patients 90 years of age or older who received radiotherapy with radical intent in eight leading institutions in Japan from 1990 through 1995.

RESULTS

Fifty-seven nonagenarian patients were studied. Their ages ranged up to 98 (median 91) and there was a strong female preponderance (M/F: 16/41). The distribution by site was as follows: head and neck, 16; skin and adnexae, 11; uterine cervix, 7; esophagus, 6. The prevailing histopathological diagnosis was squamous cell carcinoma (34), followed by adenocarcinomas (8). The highest age at RT was 98 years [female, skin cancer, died of senility 2.5 years after treatment, with no evidence of disease (NED)] and the longest survivor is 102 years old (female, glottic cancer T2, age at RT 93, alive NED for 8 years, uses wheel-chair). The rate of completion of treatment was 75% (43/57), if the treatment field was limited to the gross primary tumor volume only and if the cumulative dose was above 80% of the tolerable adult dose. Familial escort was necessary for most of the patients in completing the day-to-day RT.

CONCLUSION

Radiotherapy is feasible with radical intent even in the elderly, if the treatment field is limited to the gross primary tumor volume only, if the cumulative dose is above 80% of the tolerable adult dose and if familial support is adequate.

Curative radiotherapy with high-dose-rate brachytherapy boost for localized esophageal carcinoma: dose-effect relationship of brachytherapy with the balloon type applicator system

BACKGROUND AND PURPOSE

This study analyzed the feasibility, local control and toxicity in potentially curable patients with esophageal carcinoma treated with a combination of external irradiation and high-dose-rate (HDR) brachytherapy using a balloon type applicator system to minimize hot spots on the mucosa.

MATERIALS AND METHODS

During the 9 years, 124 patients with esophageal carcinoma and no apparent extraesophageal spread were treated with 40-60 Gy of external irradiation followed by 8-24 Gy of HDR brachytherapy. The fraction size of brachytherapy was 4-6 Gy. We developed a new applicator with 15 mm external diameter inflatable balloons. The reference point was a point 12.5 mm depth from the mid source. The study end points were local control, late toxicity and palliative effect.

RESULTS

All 124 patients completed the planned radiotherapy. Local control rate was 69/124 (56%). There was a trend toward better local control rate for T1 lesions with increasing dose via brachytherapy. Of 69 patients with local control, treatment-related ulcers occurred in 28 patients, leading to death in four. The incidence of ulcers increased with increasing brachytherapy dose; 1/6 with 12 Gy, 16/43 with 16 Gy, 6/ 12 with 20 Gy, 4/5 with 24 Gy. Esophageal benign strictures occurred in ten patients and in all cases developed from ulcers. The incidence of freedom from dysphagia was not dose-dependent.

CONCLUSION

A combination of external irradiation and HDR brachytherapy with the balloon type applicator was feasible and well tolerated. Although better local control was achieved by a higher dose of brachytherapy, the higher dose caused more severe esophageal injury.

Clinical features of esophageal cancer in the octogenarian treated by definitive radiotherapy: a multi-institutional retrospective survey

BACKGROUND

As age-related infirmity often influences treatment options and outcome of esophageal cancer, the optimization of treatment for the elderly, especially in octogenarians, has been the subject of considerable debate.

METHODS

We performed a retrospective, multi-institutional survey to assess the effect of age on the outcome of definitive radiotherapy for esophageal cancer by a questionnaire sent to eight institutions in Japan.

RESULTS

There were 362 evaluable replies. The patients included 317 males and 45 females, with a median age of 72 years (range 35-93 years), and 96% had squamous cell carcinoma. There were 30 clinical stage 1, 71 stage IIA, 17 stage IIB, 113 stage III and 116 stage IV cases. The stage was not specified in 16 cases. Multiple co-morbidities existed in 40% of the patients who were 70 years of age or older. There was no statistically significant age-related difference in the incidence of adverse reactions to radiotherapy (P > 0.05). Overall survival was more significantly affected by Karnofsky Performance Status than by the patient's age. The influence of performance status on cumulative survival for stage I and II disease was more pronounced in patients in their 80s.

CONCLUSION

The safety of radiotherapy for esophageal carcinoma is not influenced by the patient's age. Because the performance status strongly influenced survival, the multi-disciplinary assessment of functional status is mandatory for optimizing the choice of treatment for patients in their 80s with esophageal cancer.