Nomogram Predicting Overall Survival of Resected Locally Advanced Rectal Cancer Patients with Neoadjuvant Chemoradiotherapy

PURPOSE

The overall survival (OS) of resected locally advanced rectal cancer patients who underwent neoadjuvant chemoradiotherapy (nCRT) was significantly different, even among patients with the same tumor stage. The nomogram was designed to predict OS of rectal cancer with nCRT and divide the patients into different risk groups.

MATERIALS AND METHODS

Based on materials from 911 rectal cancer patients with nCRT, the multivariable Cox regression model was carried out to select the significant prognostic factors for overall survival. And then, the nomogram was formulated using these independent prognostic factors. The discrimination of the nomogram was assessed by concordance index (C-index), calibration curves and time-dependent area under curve (AUC). The patients respective risk scores were calculated through the nomogram. The best cut-off risk score was calculated to stratify the patients. The survival curves of the two different risk cohorts were performed, which assessed the predictive ability of the nomogram.

RESULTS

Age, cT stage, pretreatment CEA, pretreatment CA19-9, surgery, posttreatment CEA, posttreatment CA19-9, pT stage, pN stage and adjuvant chemotherapy were selected for the construction of the nomogram. And then the nomogram was constructed with independent prognostic factors. The C-index of the nomogram was 0.724, which showed the nomogram provided good discernment. The acceptable agreement between the predictions of nomogram and actual observations was illustrated by calibration plots for 3-, 5- and 10-year OS in the cohort. Time-dependent AUC with 6-fold cross-validation also showed consistent results of the nomogram. Risk group stratification confirmed that the nomogram had great capacity for distinguishing the prognosis.

CONCLUSION

The nomogram was developed and validated to predict overall survival of resected locally advanced rectal cancer patients with nCRT. The proposed nomogram might help clinicians to develop individualized treatment strategies. However, further studies are warranted to optimize the nomogram by finding out other unknown prognostic factors, and more external validation is still required.

[Anatomical observation and clinical significance of rectosacral fascia in total mesorectal resection]

Objective: To observe the anatomical architecture of rectosacral fascia and discuss the best plan for accurate peri-rectal dissection in laparoscopic/robotic total mesorectal resection (TME). Methods: A descriptive cohort study was carried out. A total of 127 patients with rectal cancer who underwent TME in the Department of Colorectal Surgery at the affiliated Union hospital of Fujian Medical University were included, patients' demographics with their pathological details and operation videos were collected for analysis. Another 20 high-definition images of post-TME surgical specimens were collected from our digital database. A total of 28 cadaveric models were examined at the Laboratory of Clinical Applied Anatomy, Fujian Medical University, to observe the anatomical details of rectosacral fascia. Results: (1) Anatomical observation showed that the pre-hypogastric fascia attaches to the proper fascia of the mesorectum in a horizontal arc posteriorly, forming the rectosacral fascia. If this fusion couldn't be identified and appropriately transected during posterior space dissection, it would be easy to destroy the proper fascia and dissect through the mesorectum resulting in residual mesorectum tissue. After the fascia transaction, the proper fascia of the mesorectum is still intact distally. The upper part of rectosacral fascia bilaterally re-separated again into the proper fascia and pre-hypogastric fascia. The pre-hypogastric fascia acts as a "fascia barrier" when dissecting the lateral space constantly from posterior to anterior. The right attachment of the rectosacral fascia was gradually transected. The pelvic plexus from the right S2-S4 was covered by the pre-hypogastric fascia which is considered the outer side layer of rectosacral fascia laterally. It was observed that the fascia continued with the anterior layer of the Denonvilliers' fascia, which has been transected during anterior space dissection. The proper fascia, which is the inner side layer of rectosacral fascia laterally, was still intact. The edge of the right rectosacral fascia attachment ran obliquely from the back and upward into the front direction. The left extension was similar to the right. (2) Cadaveric specimens: at the level of the lower edge of S4 vertebral body, the pre-hypogastric fascia fused with the proper fascia to form the rectosacral fascia. The right attachment margin of the rectosacral fascia was cut off step by step. The attachment margin of the rectosacral fascia went from the back and upward to the front downward direction. The right edge of rectosacral fascia attachment continued with the anterior layer of the Denonvilliers' fascia at the pre-rectal space and attached to the pre-hypogastric fascia laterally. The pelvic plexus sends out many tiny rectal branches on the anterolateral side, which pass through the transitional area between pre-hypogastric fascia and the anterior layer of the Denonvilliers' fascia to innervate the rectum. (3) TME specimens observation: the posterior attachment of rectosacral fascia was curved around the mesorectum with bilateral oblique attachments. The mesorectum was covered by fusion fascia below the posterior and bilateral attachment margin while it was covered only by the proper fascia above it. Conclusion: according to the morphological characteristics of rectosacral fascia, the rectosacral fascia should be dissected at the level of S4 vertebral body posterior to the rectum in an arc, shape and then enter the superior-levator space. Before dissecting the bilateral spaces, the anterior space of the rectum should be dissected first. The anterior layer of the Denonvilliers' fascia should be cut off into an inverted "U" shape, and then the lateral space should be dissected from anterior to posterior. Finally, the lateral attachment of rectosacral fascia was transected to ensure the integrity of the mesorectum without damaging the pelvic plexus branches and NVB.

A nomogram for predicting rectovaginal fistula after low anterior resection for rectal cancer

PURPOSE

Rectovaginal fistula (RVF) is a complicated and troublesome complication of low anterior resection (LAR) for rectal cancer. We aimed to investigate the risk factors for post-LAR RVF and develop a predictive nomogram.

METHODS

We performed a retrospective analysis of 821 female patients with rectal cancer who underwent LAR between October 2010 and October 2018. Logistic regression was performed to identify risk factors. A nomogram was developed to predict RVF.

RESULTS

The incidence of post-LAR RVF was 3.4% (28/821). A multivariate analysis showed that the preoperative serum hemoglobin level (OR 2.449, 95% CI 1.144-5.239), the distance between the tumor and anal verge (OR 4.158, 95% CI 1.392-12.418), surgical procedure (OR 2.369, 95% CI 1.117-5.027), hysterectomy (OR 2.996, 95% CI 1.106-8.833), and bilateral oophorectomy (OR 5.823, 95% CI 1.639-20.689) were significantly associated with the development of RVF. A nomogram was developed, which showed a C-index of 0.824 (95% CI 0.730-0.918) and an adjusted C-index of 0.790.

CONCLUSION

This study identified the preoperative serum hemoglobin level, the distance between the tumor and the anal verge, the type of surgical procedure, hysterectomy, and bilateral oophorectomy as predictors of post-LAR RVF. A nomogram was successfully developed. It could aid in the prediction of RVF in patients undergoing LAR.

A Four Gene-Based Risk Score System Associated with Chemoradiotherapy Response and Tumor Recurrence in Rectal Cancer by Co-Expression Network Analysis

Aim

Resistance to neoadjuvant chemoradiotherapy (NCRT) and tumor recurrence presents a major clinical problem in locally advanced rectal cancer (LARC) patients. This study aimed to explore a genetic risk score related to NCRT response and tumor recurrence in rectal cancer after NCRT.

Materials and Methods

Weighted gene co-expression network analysis was employed to identify hub genes associated with NCRT response from the GSE93375 dataset. Prognostic hub genes were determined using Cox regression analysis and associated with disease-free survival (DFS). A risk score system was constructed and the prognostic significance of the risk score was validated in our patient cohort. A predictive nomogram for DFS was developed and validated internally.

Results

The Tan module had the highest correlations with NCRT response. Ten hub genes (COL15A1, THBS2, ITGB1, MMP2, CD34, SPARC, NOTCH3, PDGFRB, DCN, and SERPINH1) were associated with NCRT response. Immunostaining expression of four genes (NOTCH3, SPARC, DCN, and ITGB1) was found to be significantly associated with both NCRT response and DFS in our patient cohort and was selected to build a prognostic risk score for DFS as follows: risk score= (0.6188×Exp _NOTCH3 ) + (0.6511×Exp _SPARC ) + (-0.2976×Exp _DCN ) + (1.0035×Exp _ITGB1 ). Using this risk score, patients could be separated into high- and low-risk groups for tumor recurrence. A nomogram that incorporated the risk score, ypTNM stage, and tumor regression grade (TRG) was constructed and utilized to predict DFS in LARC patients.

Conclusion

The four-gene expression-based risk score system presented here could be potentially used for predicting tumor recurrence in LARC patients after NCRT.

A Comprehensive Repertoire of Transfer RNA-Derived Fragments and Their Regulatory Networks in Colorectal Cancer

To provide systematic insight into the composition and expression of transfer RNA (tRNA) derivatives transcriptome in colorectal cancer (CRC). tRNA derivatives expression profiles in three pairs of CRC and adjacent normal colon tissues were performed by tRNA-derived small RNA fragments (tRFs) and tRNA halves (tiRNA) sequencing, and microarray data of transcriptomes from CRC and paired controls were retrieved from Gene Expression Omnibus database. The differentially expressed tRFs and tiRNAs and differentially expressed genes between CRC and paired normal samples were screened. The functional regulations between tRF and tiRNA and gene were identified. A total of 60 upregulated and 48 downregulated tRNA derivatives and 7373 upregulated and 12,138 downregulated messenger RNA (mRNA) were identified. The tRF and tiRNA-gene regulatory modules were constructed by analyzing computational tRF and tiRNA-target predictions and inverse expression relationships between tRF and tiRNAs and mRNA. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway annotation showed that the function of targets of tiRNA-Tyr-GTA was mainly enriched in negative regulation of epithelial cell apoptotic process and peroxisome proliferator activated-receptors (PPAR) signaling pathway. Cellular response to monoamine stimulus and inflammatory bowel disease was enriched in function of tiRNA-Val-CAC. Two functions, including negative regulation of c-Jun N-terminal kinase (JNK) cascade and choline metabolism in cancer, were enriched in tRF-Gln-CTG. The function of mesenchymal to epithelial transition was enriched in tRF-Leu-TAG. For the first time to our knowledge, our study provided a landscape of tRNA derivatives expression profiles in CRC. Further tRF and tiRNA-gene regulatory modules construction explored the potential functions related to these tRNA derivatives in the pathogenesis of CRC.

High SPRR1A expression is associated with poor survival in patients with colon cancer

High expression of small proline-rich protein 1A (SPRR1A) has been shown to be associated with tumor prognosis; however, the association between SPRR1A expression and colon cancer prognosis remains unclear. The present study sought to evaluate the association between SPRR1A expression and the clinicopathological characteristics of colon cancer, and to examine its potential prognostic value. A total of 114 patients with colon cancer were included. SPRR1A expression was evaluated by immunohistochemical staining, and the association between SPRR1A expression and clinicopathological parameters was analyzed. The prognostic value of SPRR1A was analyzed by Cox regression analysis, the Oncomine database and the R2 platform. SPRR1A expression was significantly increased in cancerous tissues compared with that in adjacent non-cancerous tissues. SPPRR1A expression was significantly associated with lymph node invasion. High SPRR1A expression was significantly associated with worse overall and disease-free survival rate. Cox regression analysis revealed that T stage, pathological N stage and high SPRR1A expression remained independent predictors for overall survival rate. The Oncomine database analysis demonstrated that SPRR1A mRNA expression levels were significantly increased in colorectal cancer tissues compared with those in adjacent non-cancerous tissues, and high SPRR1A expression was associated with a significantly worse event- and relapse-free survival time in the R2 platform. The data indicate that SPRR1A may serve as a potential biomarker for the prognosis of colon cancer.

Silencing Signal Transducer and Activator of Transcription 3 (STAT3) and Use of Anti-Programmed Cell Death-Ligand 1 (PD-L1) Antibody Induces Immune Response and Anti-Tumor Activity

BACKGROUND The treatment of cancer is still unable to meet the needs of patients and remains a huge challenge. This study investigated the immune response and anti-cancer effect of silencing STAT3 combined with the use of anti-PD-L1 antibody. MATERIAL AND METHODS Transfected CT26.WT cells were used to subcutaneously inoculate C57B/L6 mice, which were subsequently injected with anti-PD-L1 antibody. Treated mice were examined for tumor formation and inflammation using HE staining. Tumors were investigated for apoptosis using the TUNEL assay. The expression of STAT3, PD-L1, and C-met was studied immunohistochemistrially and by using PCR and Western blot analysis. RESULTS Four weeks after inoculation, tumors were observed in the inoculated mice. HE staining showed obvious inflammation in mice injected with cells that were silenced for STAT3 and injected with PD-L1 antibody. TUNEL assay showed low level of apoptosis in mice injected with cells silenced for STAT3 or injected with PD-L1 antibody, and higher level of apoptosis following combined treatment of STAT3 silencing and PD-L1 antibody injection. Immunohistochemistry, PCR, and Western blot analyses revealed that the expression of C-met, PD-L1, and STAT3 was significantly reduced in tumors following the combined treatment. Compared with treatment of STAT3 silencing or PD-L1 antibody injection, the combined treatment enhanced apoptosis. CONCLUSIONS Silencing STAT3 and PD-L1 antibody injection in combination increased apoptosis in tumor cells and thus offers better anti-cancer activity.

[Robotic surgical approach for rectal cancer]

Total mesorectal excision (TME) is the standard operation for mid-low rectal cancer. The advancement of minimally invasive surgery for rectal cancer has never been interrupted, from the conventional open surgery and laparoscopic surgery to robotic surgery and similarly from the conventional transabdominal approach to the transanal approach. All these approaches have focused on ensuring oncological control and meanwhile minimizing surgical trauma, preserving pelvic autonomic nerves, accelerating postoperative recovery and rehabilitation accordingly. In this review, we summarized the current progress of robotic TME for the treatment of rectal cancer and evaluated its safety and efficiency from the perspective of oncological and functional outcomes. The advantages behind robotic TME rely mainly on dealing with difficult rectal cancer cases. Besides, the robotic surgery system shortens the learning curve. However, the superiority of robotic surgery in preserving autonomic nerve has not been yet confirmed compared with laparoscopic surgery. We proposed the partial preservation of Denonvilliers' fascia during robotic TME, in order to enlarge the pelvic space, ensure the integrity of anterior mesorectum, and preserve the autonomic nerves. To date, there is still a lack of evidence regarding robotic taTME in the treatment of rectal cancer. However, several technical defects regarding taTME itself, including the residual of the terminal mesorectum, the sacrifice of distal rectal stump, and cancer cell dissemination due to airflow during dissection, need to be solved. The reported higher rate of local recurrence with multifocal pelvic side involvement and the anorectal dysfunction after taTME restrict its widespread performance.

[Rectum-preserving surgery after consolidation neoadjuvant therapy or totally neoadjuvant therapy for low rectal cancer: a preliminary report]

Objective: To investigate the feasibility and safety of sphincter-preserving surgery after neoadjuvant chemoradiotherapy (nCRT) with consolidation chemotherapy in the interval period or total neoadjuvant therapy (TNT) for low rectal cancer. Methods: A descriptive case series study was carried out. Clinical data of patients with locally advanced low rectal cancer (LALRC) who achieved complete clinical response (cCR) or nearly cCR (near-cCR) after nCRT at the Department of Colorectal Surgery of Fujian Medical University Union Hospital from May 2015 to February 2019 were retrospectively analyzed. Case inclusion criteria: (1) Low rectal adenocarcinoma within 6 cm from the anal verge. (2) After nCRT, tumor presented markedly regression as mucosal nodule or abnormalities, superficial ulcer, scar or a mucosal erythema (< 2 cm); no regional lymph node metastasis or distant metastasis was found in rectal ultrasonography, pelvic MRI and PET-CT; MRI showed obvious fibrosis in the original tumor site; and post-treatment CEA was normal. (3) The patient and the family members adhered to receive the transanal full-thickness local excision with informed consent. (4) When the residual lesions were difficult to detect after nCRT, patients received the watch and wait (W&W) strategy. Exclusion criteria: (1) Before nCRT, pathological results showed poorly differentiated or signet-ring cell carcinoma; lateral lymph node metastasis was suspected. (2) When the residual lesion size was more than 3 cm after nCRT, it was difficult to perform local excision. The consolidation nCRT group received 3-4 cycles of CAPOX regimen (oxaliplatin and capecitabine) or six cycles of mFOLFOX6 (oxaliplatin, leucovorin, and 5-fluorouracil) combined with the long-course radiotherapy (intensity-modulated radiation therapy with a total dose of 50.4Gy). Patients with concurrent chemotherapy more than or equal to five cycles of CAPOX or eight cycles of mFOLFOX6 were defined as total neoadjuvant therapy (TNT) group. Local resection was recommended for patients who were near-cCR according to modified MSKCC criteria 8-33 weeks after the end of radiotherapy. Patients with a near-cCR, who were judged as ycN0 according to PET-CT and MRI and were ypT0 after local excision, could enter the W&W strategy. Patients with pathologic stage more advanced than ypT1, and those with positive resection margin, or lymphovascular invasion were recommended for salvage radical surgery after local excision. The ypT1 patients with a negative resection margin and without lymphovascular invasion might receive the W&W management carefully if they refused radicalsurgery to sacrifice the sphincter for low rectal cancer. Results: Of 32 patients, 14 were males and 18 were females with the average age of 59 years old. Twenty-three patients underwent consolidation nCRT, and 9 received TNT. The first evaluation after treatments showed 19 cases with cCR and 13 with near-cCR. Twenty-nine patients received local excision while 3 patients with undetectable lesions received W&W policy. Four cases (12.5%) underwent salvage radical surgery with abdominoperineal resection. After local excision, 3 cases underwent salvage radical surgery immediately, and the final pathologic result was ypT3N0, ypT2N0, and ypT2N0 respectively, of whom 2 cases were in the group of consolidation CRT and 1 was in the TNT group. Of these 3 cases, 1 case with an initial cT3 stage showed a pathologic stage of ypT1 and a negative circumferential resection margin after consolidation nCRT and local excision, however, the final pathologic stage was ypT3 with fragmented tumor deposits in the mesorectum after the salvage radical surgery. Meanwhile 1 patient in the TNT group receiving W&W suffered from intraluminal regrowth after 7.4 months follow-up and underwent salvage abdominoperineal resection. One patient in the consolidation nCRT group died of stroke 42.5 months after local resection. Another patient in the TNT group had cerebral metastasis 10 months after the W&W policy, but no local recurrence was found in the pelvic cavity, then received resection of the metastatic tumors. The average follow-up for all the patients was 23 (5-51) months. The cumulative local regrowth rate was 5.0%. The overall survival rate was 85.7%, and the sphincter-preservation rate was increased from 25.0% (28/32) in the original plan to 87.5% (28/32) actually. The 3-year disease-free survival rate was 89.7%. The 3-year organ-preserving survival rate was 85.7%, and the 3-year stoma-free survival rate was 82.5%. At present, 31 patients still survived. Conclusions: After nCRT with consolidation chemotherapy or TNT for low rectal cancer, patients with cCR, ycN0 according to PET-CT and MRI, and ypT0 after local excision, can consider the W&W strategy. Strict patient selection with a near-cCR for local resection and sphincter-preserving strategy can reduce the local regrowth of cancer, and the short-term outcomes are satisfactory.

FBXW4 Acts as a Protector of FOLFOX-Based Chemotherapy in Metastatic Colorectal Cancer Identified by Co-Expression Network Analysis

Background

FOLFOX chemotherapy is one of the most commonly used treatments for colorectal cancer (CRC) patients. However, the efficacy and tolerance of FOLFOX therapy varies between patients. The purpose of this study was to explore hub genes associated with primary chemotherapy-resistance and to explore the possible mechanisms involved from non-European patients.

Method

A weighted gene co-expression network was constructed to identify gene modules associated with chemotherapy resistance in mCRC from China.

Results

A Gene Array Chip was used to detect mRNA expression in 11 mCRC patients receiving preoperative FOLFOX chemotherapy. The immune response was associated with chemotherapy-resistance in microarray data. Through the use of WGCNA, we demonstrated that the crucial functions enriched in chemotherapy-resistance modules were cell proliferation, MAPK signaling pathways, and PI3K signaling pathways. Additionally, we identified and validated FBXW4 as a new effective predictor for chemotherapy sensitivity and a prognostic factor for survival of CRC patients by using our own data and GSE69657. Furthermore, a meta-analysis of 15 Gene Expression Omnibus–sourced datasets showed that FBXW4 messenger RNA levels were significantly lower in CRC tissues than in normal colon tissues. An analysis of the data from the R2: Genomics Analysis and Visualization Platform showed that low FBXW4 expression was correlated with a significantly worse event- and relapse-free survival. Gene set enrichment analysis showed that the mechanism of FBXW4-mediated chemotherapy resistance may involve the DNA replication signal pathway and the cell cycle.

Conclusion

FBXW4 is associated with chemotherapy resistance and prognosis of CRC probably by regulating DNA replication signaling pathways and the cell cycle.

Prognostic impact of preoperative immunonutritional status in rectal mucinous adenocarcinoma

Aim: To explore the impact of preoperative the albumin-to-globulin ratio (AGR) and the prognostic nutritional index (PNI) on prognosis in rectal mucinous adenocarcinoma (MAC). Methods: A total of 128 patients were included. Results: According to the X-tile analysis, cutoff values of AGR and PNI were 1.1 and 43.8. Preoperative AGR (p = 0.041), preoperative PNI (p = 0.036) and pTNM stage (p = 0.003) were independently associated with overall survival in rectal MAC patients. Distance from the anal verge (p = 0.005), preoperative AGR (p = 0.021), preoperative PNI (p = 0.007) and pTNM stage (p < 0.001) were significantly associated with disease-free survival in rectal MAC patients. Nomograms for overall survival and disease-free survival were developed (C-index: 0.739 and 0.764). Conclusion: Preoperative AGR and PNI can act as effective predictors for survival for rectal MAC patients.

The 'multilayer' theory of Denonvilliers' fascia: anatomical dissection of cadavers with the aim to improve neurovascular bundle preservation during rectal mobilization

AIM

Denonvilliers' fascia is thought to be a multilayered fascial structure, based on its embryological development with the neurovascular bundle embedded within it. Recently, this theory had been proven histologically and by confocal microscopy in many published articles. However, the literature does not report on how surgeons can identify these structures. We aimed to determine the optimal surgical approach for preserving these critical structures.

METHOD

Eighteen cadavers (13 male/five female) were included and treated according to the ethical considerations stated in the donation consent of our institution. Dissection was performed with the assistance of binocular loupes for better anatomical detail. The compositions of the prerectal fascia and the neurovascular bundle were observed and recorded at different levels of dissection using a high-definition camera.

RESULTS

The theoretical multilayered fascia was found in male specimens as three fascial layers originating from the perineal body, seminal vesicles and posterior bladder neck. The first layer merged posterolaterally and fused with the rectosacral fascia (Waldeyer's fascia). The neurovascular bundle in male specimens was observed piercing the second and third layers, while the first layer acted as a protective cover. Dissection of female specimens demonstrated only one layer in the prerectal space.

CONCLUSION

Intiating anterior rectal mobilization by incising the peritoneum posterior to its reflection seems to be anatomically correct to preserve DVF. However, its applicability may be difficult in a narrow chanllenging pelvis. The lateral rectal ligaments and Waldeyer's fascia should be dissected from their attachments to the proper fascia of the rectum.

Downregulated SPINK4 is associated with poor survival in colorectal cancer

BACKGROUND

SPINK4 is known as a gastrointestinal peptide in the gastrointestinal tract and is abundantly expressed in human goblet cells. The clinical significance of SPINK4 in colorectal cancer (CRC) is largely unknown.

METHODS

We retrieved the expression data of 1168 CRC patients from 3 Gene Expression Omnibus (GEO) datasets (GSE24551, GSE39582, GSE32323) and The Cancer Genome Atlas (TCGA) to compare the expression level of SPINK4 between CRC tissues and normal colorectal tissues and to evaluate its value in predicting the survival of CRC patients. At the protein level, these results were further confirmed by data mining in the Human Protein Atlas and by immunohistochemical staining of samples from 81 CRC cases in our own center.

RESULTS

SPINK4 expression was downregulated in CRC compared with that in normal tissues, and decreased SPINK4 expression at both the mRNA and protein levels was associated with poor prognosis in CRC patients from all 3 GEO datasets, the TCGA database and our cohort. Additionally, lower SPINK4 expression was significantly related to higher TNM stage. Moreover, in multivariate regression, SPINK4 was confirmed as an independent indicator of poor survival in CRC patients in all databases and in our own cohort.

CONCLUSIONS

We concluded that reduced expression of SPINK4 relates to poor survival in CRC, functioning as a novel indicator.

[Identification of gene biomarkers to predict responses to neoadjuvant chemoradiotherapy in patients with rectal cancer and pathways enrichment analysis]

Objective: To screen out the potential gene biomarkers to predict responses to neoadjuvant chemoradiotherapy (CRT) in patients with rectal cancer and to explore the main downstream pathways of resistance. Methods: The gene expression profiles (GSE35452) of locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy from 46 specimens (24 responders, TRG 0/1, and 22 non-responders, TRG 2/3) were downloaded from the GEO database. The differentially expressed genes were identified to screen out the potential biomarkers by use of the GCBI platform. GO and KEGG pathways enrichment analysis were performed to integrate enrichment results of differentially expressed genes. Signal-signal interaction network was constructed and analyzed to screen out potential main downstream pathways. Results: A total of 1079 differentially expressed genes were screened, including 657 up-regulated and 422 down-regulated ones. Among these genes, REG4 had the maximum fold change value of -6.029 491. In GO term, these differentially expressed genes were mainly enriched in molecule metabolic process, cell cycle, DNA-dependent transcription, signal transduction and apoptotic process. The KEGG pathways enrichment analysis showed that the differentially expressed genes were enriched in 65 KEGG pathways, including metabolic pathways, cell cycle and metabolism pathways. Signal-signal interaction network analysis showed that MAPK signaling pathway and cell cycle pathway might play a determinant role in the development of neoadjuvant chemoradiotherapy resistance. Further analysis showed that CDKN1B, CDKN2A, RBL1, TFDP1, CCND2, CCNE2, CDC6 and CDK6 in cell cycle might induce chemoradiotherapy resistance by blocking G1/S phase cell cycle arrest, decreasing the apoptosis of tumor cells and increasing S phase ratio of chemoradiotherapy resistance. Conclusion: G1/S phase cell cycle arrest blocking plays an important role in the development of chemoradiotherapy resistance in patients with rectal cancer. Moreover, the key genes, such as REG4, may be useful in predicting responses to neoadjuvant chemoradiotherapy.

Demethylation and Overexpression of CSF2 are Involved in Immune Response, Chemotherapy Resistance, and Poor Prognosis in Colorectal Cancer

Purpose

This study aimed to evaluate the role of colony-stimulating factor 2 (CSF2) in chemotherapy resistance, prognosis, and immune response and to identify its possible mechanisms underlying drug resistance.

Methods

Drug-resistant cell lines were obtained by successively increasing drug concentration. RNA-Seq was performed to screen hub genes. CSF2 expression was analyzed via immunohistochemistry. Moreover, The Cancer Genome Atlas (TCGA), Tumor Immune Estimation Resource (TIMER) dataset, and R2 platform were used to explore the correlations among CSF2 expression, prognosis, and immune response.

Results

RNA-Seq indicated that microRNAs in cancer, P53 signaling pathway, and cell cycle were associated with FOLFOX chemotherapy resistance. Protein-protein interaction (PPI), molecular complex detection (MOCDE), and qRT-PCR analysis verified CSF2 as the hub gene in chemotherapy resistance. Moreover, CSF2 expression was lower in the normal tissue than in the cancerous tissue (P<0.05). Higher expression of CSF2 was associated with poor OS and DFS in colon cancer patients (P<0.05). We further found similar results in the Oncomine database and R2 platform (P<0.05). A higher expression of CSF2 in the CRC tissue may be caused by demethylation, which was verified using the TCGA datasets. Moreover, GSEA demonstrated that CSF2 was associated with immune response, which was consistent with results reported using TIMER datasets.

Conclusion

CSF2 is a novel biomarker and a prognostic factor for the survival of CRC patients affecting the immune response, and an overexpression of CSF2 in CRC patients may be caused by DNA demethylation.

A 3-circular RNA signature as a noninvasive biomarker for diagnosis of colorectal cancer

Background

Circular RNAs (circRNAs), a novel type of noncoding RNAs, play critical roles in the initiation and progression of cancer. Emerging studies also shows that circRNAs may function as potential markers for cancer diagnosis and treatment. However, the diagnostic value of circRNAs in colorectal cancer (CRC) remains need to be unearthed.

Methods

CircRNA microarray was performed to detect the differentially expressed circRNAs in eight plasma samples, including four colorectal cancer (CRC) and four normal samples. Besides, the results of microarray were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, ROC curve evaluation was performed to calculate the diagnostic value of significantly dysregulated circRNAs. In order to predict the potential mechanism of the significant circRNAs, circRNA-miRNA-mRNA network was constructed based on the TargetScan, miRTarBase and MIRDB database, as well as CircInteractome online software. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to further predict the function of meaningful circRNAs.

Results

Totally three differentially expressed circRNAs were identified in CRC plasma compared to normal plasma by circRNA microarray analysis, and the results was validated by qRT-PCR. Hsa_circ_0082182, hsa_circ_0000370 and hsa_circ_0035445 were identified and ROC curves analysis was used to calculate the single and joint diagnostic value. Furthermore, GO and KEGG analyses revealed that functions were mainly cancer-related, which indicated that the circRNAs were meaningfully associated with CRC cell proliferation and metastasis.

Conclusion

In conclusion, we have identified three circRNAs that are dysregulated in CRC plasma, including hsa_circ_0082182, hsa_circ_0000370 and hsa_circ_0035445. ROC curves showed that these circRNAs might have diagnostic value for colorectal cancer. Furthermore, bioinformatics analysis indicated that the above-mentioned circRNAs might be involved in the development of CRC.

An Integrated miRNA-lncRNA Signature Predicts the Survival of Stage II Colon Cancer

OBJECTIVE

By in silico analysis of colon cancer data from the Cancer Genome Atlas (TCGA) database, we develop a prognostic signature to improve the stratification of high-risk stage II colon cancer patients.

METHOD

RNA sequencing (RNA-Seq) data from 187 stage II colon cancer patients was obtained from the TCGA data portal. We excluded cases without a sufficient amount of survival data (n=21), leaving 166 stage II colon cancer patients to be selected for further survival analysis. Differentially expressed lncRNAs and miRNAs were unveiled by the edgeR package of R. A comprehensive ceRNAs regulatory network was constructed using the Cytoscape. Cox regression analysis was performed to screen prognostic RNAs and develop a prognostic signature. The Multi Experiment Matrix and Gene Ontology were undertaken to assess the prognostic lncRNA MIR31HG function.

RESULTS

The multivariate analysis indicates that 2 lncRNAs (WASIR2 and MIR31HG) and 2 miRNAs (hsa-mir-200a and hsa-mir-155) exhibited an independently significant prognostic value for stage II colon cancer. The 4 lncRNA-miRNA signatures for predicting the overall survival (OS) was constructed with the formula: Risk score=exp WASIR2*(0.213)+exp MIR31HG*(0.152)+exp hsa-mir-200a*(-0.329)+exp hsa-mir-155*(0.300). The area under the curve in the receiver operating characteristic analysis was 0.810. Kaplan-Meier survival curves confirm that the low-risk group had a low death rate, with a 5-year OS rate at 87.7%. However, the high-risk group had a low 5-year OS of 23.1% (P=0.000). The correlative genes of MIR31HG were found to be enriched in the epithelial-to-mesenchymal transition pathway, and the VEGFR3 signaling in lymphatic endothelium pathways.

CONCLUSIONS

These findings indicate that the 4 lncRNA-miRNA prognostic signature could be a marker for survival of stage II colon cancer patients.

LNRRIL6, a novel long noncoding RNA, protects colorectal cancer cells by activating the IL-6-STAT3 pathway

Long noncoding RNAs (lncRNAs) are emerging as critical regulators of cancer. There is a comparable number of lncRNAs to protein‐coding genes, but the expression patterns, functions, and molecular mechanisms of most lncRNAs in colorectal cancer (CRC) remain unclear. In this study, we report the identification of a novel lncRNA, named long noncoding RNA regulating IL‐6 transcription (LNRRIL6), which is upregulated in CRC tissues and cell lines. Increased LNRRIL6 expression is associated with aggressive clinicopathological characteristics and poor prognosis of CRC patients. Functional experiments showed that enhanced expression of LNRRIL6 promotes CRC cell proliferation and survival in vitro and CRC tumor growth in vivo. Conversely, depletion of LNRRIL6 inhibits CRC cell proliferation and survival in vitro and CRC tumor growth in vivo. Mechanistically, we revealed that LNRRIL6 physically binds to the IL‐6 promoter, thereby increasing IL‐6 transcription, inducing IL‐6 autocrine signaling, and activating the IL‐6/STAT3 pathway. The expression of IL‐6 is positively associated with that of LNRRIL6 in CRC tissues. Blocking the IL‐6/STAT3 pathway using the FDA‐approved IL‐6‐receptor antagonist antibody, tocilizumab, abolished the oncogenic role of LNRRIL6 in CRC. Taken together, these findings identify a novel lncRNA, LNRRIL6, that promotes CRC cell survival through activation of the IL‐6/STAT3 pathway and suggest that LNRRIL6 may be a potential prognostic biomarker and therapeutic target for CRC.

Neoadjuvant Modified FOLFOX6 With or Without Radiation Versus Fluorouracil Plus Radiation for Locally Advanced Rectal Cancer: Final Results of the Chinese FOWARC Trial

PURPOSE

In the multicenter, open-label, phase III FOWARC trial, modified infusional fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus radiotherapy resulted in a higher pathologic complete response rate than fluorouracil plus radiotherapy in Chinese patients with locally advanced rectal cancer. Here, we report the final results.

METHODS

Adults ages 18 to 75 years with stage II/III rectal cancer were randomly assigned (1:1:1) to five cycles of infusional fluorouracil (leucovorin 400 mg/m², fluorouracil 400 mg/m², and fluorouracil 2.4 g/m² over 48 hours) plus radiotherapy (46.0 to 50.4 Gy delivered in 23 to 25 fractions during cycles 2 to 4) followed by surgery and seven cycles of infusional fluorouracil, the same treatment plus intravenous oxaliplatin 85 mg/m² on day 1 of each cycle (mFOLFOX6), or four to six cycles of mFOLFOX6 followed by surgery and six to eight cycles of mFOLFOX6. The primary end point was 3-year disease-free survival (DFS).

RESULTS

In total, 495 patients were randomly assigned to treatment. After a median follow-up of 45.2 months, DFS events were reported in 46, 39, and 46 patients in the fluorouracil plus radiotherapy, mFOLFOX6 plus radiotherapy, and mFOLFOX6 arms. In each arm, the probability of 3-year DFS was 72.9%, 77.2%, and 73.5% (P = .709 by the log-rank test), the 3-year probability of local recurrence after R0/1 resection was 8.0%, 7.0%, and 8.3% (P = .873 by the log-rank test), and the 3-year overall survival rate was 91.3%, 89.1%, and 90.7% (P = .971 by log-rank test), respectively.

CONCLUSION

mFOLFOX6, with or without radiation, did not significantly improve 3-year DFS versus fluorouracil with radiation in patients with locally advanced rectal cancer. No significant difference in outcomes was found between mFOLFOX6 without radiotherapy and fluorouracil with radiotherapy, which requires additional investigation of the role of radiotherapy in these regimens.