Efficacy and safety of preoperative immunotherapy in patients with mismatch repair-deficient or microsatellite instability-high gastrointestinal malignancies

BACKGROUND Programmed death protein(PD)-1 blockade immunotherapy significantly prolongs survival in patients with metastatic mismatch repair-deficient(dMMR)/microsatellite instability-high(MSI-H)gastrointestinal malignancies such gastric and colorectal cancer.However,the data on preoperative immunotherapy are limited.AIM To evaluate the short-term efficacy and toxicity of preoperative PD-1 blockade immunotherapy.METHODS In this retrospective study,we enrolled 36 patients with dMMR/MSI-H gastrointestinal malignancies.All the patients received PD-1 blockade with or without chemotherapy of CapOx regime preoperatively.PD1 blockade 200 mg was given intravenously over 30 min on day 1 of each 21-d cycle.RESULTS Three patients with locally advanced gastric cancer achieved pathological complete response(pCR).Three patients with locally advanced duodenal carcinoma achieved clinical complete response(cCR),followed by watch and wait.Eight of 16 patients with locally advanced colon cancer achieved pCR.All four patients with liver metastasis from colon cancer reached CR,including three with pCR and one with cCR.pCR was achieved in two of five patients with nonliver metastatic colorectal cancer.CR was achieved in four of five patients with low rectal cancer,including three with cCR and one with pCR.cCR was achieved in seven of 36 cases,among which,six were selected for watch and wait strategy.No cCR was observed in gastric or colon cancer.CONCLUSION Preoperative PD-1 blockade immunotherapy in dMMR/MSI-H gastrointestinal malignancies can achieve a high CR,especially in patients with duodenal or low rectal cancer,and can achieve high organ function protection.

Intestinal stem cell marker LGR5 expression during gastric carcinogenesis

AIM:To investigate the differential expression of leu-cine-rich repeat-containing G protein-coupled receptor5(LGR5)in gastric cancer tissues and its significance related to tumor growth and spread.METHODS:Formalin-fixed biopsy specimens of intestinal metaplasia(n=90),dysplasia(n=53),gastric adenocarcinoma(n=180),metastases in lymph nodes and the liver(n=15),and lesion-adjacent normal gastric mucosa(controls;n=145)were obtained for analysis from the Peking University Cancer Hospital’s Department of Pathology and Gastrointestinal Surgery tissue archives(January 2003 to December 2011).The biopsied patients’demographic and clinicopathologic data were retrieved from the hospital’s medical records database.Each specimen was subjected to histopathological typing to classify the tumor node metastasis(TNM)stage and to immunohistochemistry staining to detect the expression of the cancer stem cell marker LGR5.The intergroup differences in LGR5 expression were assessed by Spearman’s rank correlation analysis,and the relationship between LGR5 expression level and the patients’clinicopathological characteristics was evaluated by theχ2test or Fisher’s exact test.RESULTS:Significantly more gastric cancer tissues showed LGR5+staining than normal control tissues(all P<0.01),with immunoreactivity detected in 72.2%(65/90)and 50.9%(27/53)of intestinal metaplasia and dysplasia specimens,respectively,52.8%(95/180)of gastric adenocarcinoma specimens,and 73.3%%(11/15)of metastasis specimens,but 26.9%(39/145)of lesion-adjacent normal gastric mucosa specimens.Comparison of the intensity of LGR5+staining showed an increasing trend that generally followed increasing dedifferentiation and tumor spread(normal tissue<dysplasia,<gastric adenocarcinoma<metastasis;all P<0.001),with the exception of expression level detected in intestinal metaplasia which was higher than that in normal gastric tissues(P<0.001).Moreover,gastric cancer-associated enhanced expression of LGR5 was found to be signifcantly associated with age,tumor differentiation,Lauren type and TNM stage(Ⅰ+ⅡvsⅢ+Ⅳ)(all P<0.05),but not with sex,tumor site,location,size,histology,lymphovascular invasion,depth of invasion,lymph node metastasis or distant metastasis.Patients with LGR5+gastric cancer specimens and without signs of metastasis from the original biopsy experienced more frequent rates of recurrence or metastasis during follow-up than patients with LGR5-specimens(P<0.05).CONCLUSION:Enhanced LGR5 is related to progressive dedifferentiation and metastasis of gastric cancer,indicating the potential of this receptor as an early diagnostic and prognostic biomarker.

Significance of HER2 protein expression and HER2 gene amplification in colorectal adenocarcinomas

BACKGROUND Human epidermal growth factor receptor 2(HER2) is an oncogenic driver, and a well-established therapeutic target in breast and gastric cancers. While the role of HER2 as a prognostic biomarker in colorectal adenocarcinomas(CRCs) remains uncertain, its relevance as a therapeutic target has been established. We undertook the present study to evaluate the frequency of HER2 expression in CRC and to correlate it with various clinicopathological variables.AIM To correlate HER2 protein expression and HER2 gene amplification with clinicopathological features and survival in surgically resected CRC.METHODS About 1195 consecutive surgically resected CRCs were analyzed by immunohistochemical staining(IHC) to assess HER2 protein expression, and 141 selected tumors were further evaluated by fluorescence in situ hybridization(FISH) to assess HER2 gene amplification. Follow-up information was availablefor 1058 patients, and using this information we investigated the prevalence of HER2 protein overexpression and gene amplification in a large series of surgically resected CRCs, and evaluated the relationship between overexpression and clinicopathological parameters and prognosis.RESULTS HER2 IHC scores of 3+, 2+, 1+, and 0 were seen in 31(2.6%), 105(8.8%), 475(39.7%), and 584(48.9%) tumors, respectively. HER2 gene amplification was seen in 24/29 tumors with an IHC score of 3+(82.8%; unreadable in 2/31), 12/102 tumors with an IHC score of 2+(11.8%; unreadable in 2/104), and 0 tumors with IHC score of 1+(0/10). HER2 gene amplification was seen in 36/1191 tumors(3.0%; unreadable in 4/1195). Among the tumors with HER2 IHC scores of 3+and 2+, the mean percentage of tumor cells with positive IHC staining was 90%(median 100%, range 40%-100%) and 67%(median 75%, range 5%-95%),respectively(P < 0.05). Among tumors with IHC scores of 2+, those with HER2 gene amplification had a higher number of tumors cells with positive IHC staining(n = 12, mean 93%, median 95%, range 90%-95%) than those without(n =90, mean 70%, median 50%, range 5%-95%)(P < 0.05). HER2 gene status was significantly associated with distant tumor metastasis and stage(P = 0.028 and0.025). HER2 protein overexpression as measured by IHC or HER2 gene amplification as measured by FISH was not associated with overall survival(OS)or disease-specific survival for the overall group of 1058 patients. However,further stratification revealed that among patients with tubular adenocarcinomas who were 65 years old or younger(n = 601), those exhibiting HER2 gene amplification had a shorter OS than those without(mean: 47.9 mo vs 65.1 mo, P =0.04). Among those patients with moderately to poorly differentiated tubular adenocarcinomas, those with positive HER2 tumor IHC scores(2+, 3+) had a shorter mean OS than those with negative HER2 IHC scores(0, 1+)(47.2 mo vs64.8 mo, P = 0.033). Moreover, among patients with T2 to T4 stage tumors, those with positive HER2 IHC scores also had a shorter mean OS than those with negative HER2 IHC scores(47.1 mo vs 64.8 mo, P = 0.031).CONCLUSION HER2 protein levels are correlated with clinical outcomes, and positive HER2 expression as measured by IHC confers a worse prognosis in those patients 65 years old or younger with tubular adenocarcinomas.

Towards personalized perioperative treatment for advanced gastric cancer

Gastric cancer is one of the most frequently diagnosed cancers worldwide. Although the rate of gastric cancer has declined dramatically over the past decades in most developed Western countries, it has not declined in East Asia. Currently, a radical gastrectomy is still the only curative treatment for gastric cancer. Over the last twenty years, however, surgery alone has been replaced by a multimodal perioperative approach. To achieve the maximum benefit from the perioperative treatment, a thorough evaluation of the tumor must first be performed. A complete assessment of gastric cancer is divided into two parts: staging and histology. According to the stage and histology of the cancer, perioperative chemotherapy or radiochemotherapy can be implemented, and perioperative targeted therapies such as trastuzumab may also play a role in this field. However, perioperative treatment approaches have notbeen widely accepted until a series of clinical trials were performed to evaluate the value of perioperative treatment. Although multimodal perioperative treatment has been widely applied in clinical practice, personalization of perioperative treatment represents the next stage in the treatment of gastric cancer. Genomic-guided treatment and efficacy prediction using molecular biomarkers in perioperative treatment are of great importance in the evolution of treatment and may become an ideal treatment method.

Laparoscopy-assisted transanal total mesorectal excision for lower rectal cancer:A feasible and innovative technique

BACKGROUND Transanal total mesorectal excision(taTME)is a new technique with many potential technical advantages.Laparoscopy-assisted taTME is a combination of transabdominal taTME and transluminal endoscopic surgery taTME.Laparoscopy-assisted taTME is a combination of techniques such as minimally invasive surgery,intersphincter-assisted resection,natural orifice extraction,ta minimally invasive surgery,and ultralow-level preservation of the anus.AIM To verify the feasibility and safety of an innovative technique of taTME for treatment of cancer located in the lower rectum.METHODS From January 2016 to March 2018,we attempted to perform laparoscopy-assisted taTME surgery in 24 patients with lower rectal cancer.RESULTS The new technique of laparoscopy-assisted taTME was successfully performed in all 24 patients.Mean operating time was 310.0 min and mean intraoperative blood loss was 69.1 mL.The mean time to passing of first flatus was 3.1 d,and mean postoperative hospital stay was 9.2 d.Two patients were given postoperative analgesics due to anal pain.Twenty-three patients were able to walk in first 2 d,and five patients had postoperative complications.CONCLUSION Laparoscopy-assisted taTME is suitable for selected patients with lower rectal cancer,and this technique is worthy of further recommendation.

Surgical intervention for malignant bowel obstruction caused by gastrointestinal malignancies

BACKGROUND Malignant bowel obstruction(MBO)is a common event for end-stage gastrointestinal cancer patients.Previous studies had demonstrated manifestations and clinical management of MBO with mixed malignancies.There still lack reports of the surgical treatment of MBO.AIM To analyze the short-term outcomes and prognosis of palliative surgery for MBO caused by gastrointestinal cancer.METHODS A retrospective chart review of 61 patients received palliative surgery between January 2016 to October 2018 was performed,of which 31 patients underwent massive debulking surgery(MDS)and 30 underwent ostomy/by-pass surgery(OBS).The 60-d symptom palliation rate,30-d morbidity and mortality,and overall survival rates were compared between the two groups.RESULTS The overall symptom palliation rate was 75.4%(46/61);patients in the MDS group had significantly higher symptom palliation rate than OBS group(90%vs 61.2%,P=0.016).Patients with colorectal cancer who were in the MDS group showed significantly higher symptom improvement rates compared to the OBS group(overall,76.4%;MDS,61.5%;OBS,92%;P=0.019).However,patients with gastric cancer did not show a significant difference in symptom palliation rate between the MDS and OBS groups(OBS,60%;MDS,80%;P=1.0).The median survival time in the MDS group was significantly longer than in the OBS group(10.9 mo vs 5.3 mo,P=0.05).CONCLUSION For patients with MBO caused by peritoneal metastatic colorectal cancer,MDS can improve symptom palliation rates and prolong survival,without increasing mortality and morbidity rates.

Myofibrillogenesis regulator-1 overexpression is associated with poor prognosis of gastric cancer patients

AIM: To investigate the expression of myofibrillogenesis regulator-1 (MR-1) in relation to clinicopathological parameters and postoperative survival in a group of Chinese patients with gastric cancer. METHODS: In our previous study of human wholegenome gene expression profiling, the differentially expressed genes were detected in the gastric cancer and its adjacent noncancerous mucosa. We found that MR-1 was associated with the location and differentiation of tumors. In this study, MR-1 protein expression was determined by immunohistochemistry in specimens of primary cancer and the adjacent noncancerous tissues from gastric cancer patients. A set of real-time quantitative polymerase chain reaction assays based on the Universal ProbeLibrary-a collection of 165 presynthesized, fluorescence-labeled locked nucleic acid hydrolysis probes-was designed specifically to detect the expression of MR-1 mRNA. The correlation was analyzed between the expression of MR-1 and other tumor characteristics which may influence the prognosis of gastric cancer patients. A retrospective cohort study on the prognosis was carried out and clinical data were collected from medical records. RESULTS: MR-1 mRNA and protein could be detected in gastric cancer tissues as well as in matched noncancerous tissues. MR-1 was up-regulated at both mRNA (5.459 ± 0.639 vs 1.233 ± 0.238, P < 0.001) and protein levels (34.2% vs 13.2%, P = 0.003) in gastric cancer tissues. Correlation analysis demonstrated that high expression of MR-1 in gastric cancer was significantly correlated with clinical stage (P = 0.034). Kaplan-Meier analysis showed that the postoperative survival of the MR-1 positive group tended to be poorer than that of the MR-1 negative group, and the difference was statistically significant (P = 0.002). Among all the patients with stageⅠ-Ⅳ carcinoma, the 5-year survival rates of MR-1 positive and negative groups were 50.40% and 12.70%, respectively, with respective median survival times of 64.27 mo (95%CI: 13.41-115.13) and 16.77 mo (95%CI: 8.80-24.74). Univariate and multivariate analyses were performed to compare the impact of MR-1 expression and other clinicopathological parameters on prognosis. In a univariate analysis on all 70 specimens, 6 factors were found to be significantly associated with the overall survival statistically: including MR-1 expression, depth of invasion, distant metastasis, lymph node metastasis, vascular invasion and the tumor node metastasis (TNM) stage based on the 7th edition of the International Union against Cancer TNM classification. To avoid the influence caused by univariate analysis, the expressions of MR-1 as well as other parameters were examined in multivariate Cox analysis. Clinicopathological variables that might affect the prognosis of gastric cancer patients were analyzed by Cox regression analysis, which showed that MR-1 expression and TNM stage were independent predictors of postoperative survival. The best mathematical multivariate Cox regression model consisted of two factors: MR-1 expression and TNM stage. Our results indicated that MR-1 protein could act as an independent marker for patient overall survival [Hazard ratio (HR): 2.215, P = 0.043]. CONCLUSION: MR-1 is an important variable that can be used to evaluate the outcome, prognosis and targeted therapy of gastric cancer patients.

Fat clearance and conventional fixation identified ypN0 rectal cancers following intermediate neoadjuvant radiotherapy have similar long-term outcomes

BACKGROUND As a prognostic factor for colorectal cancer,lymph node(LN)status,particularly the number of LN harvested,has been demonstrated to be essential in the evaluation of quality control in terms of surgical specimen.Neoadjuvant chemoradiation,however,decreases the LN harvest.Therefore,certain approaches(such as fat clearance or methylene blue)has drawn significant attention in order to raise LN yield.AIM To compare the long-term oncologic outcome of ypN0 rectal cancer identified using fat clearance(FC)or conventional fixation(CF)following 30 Gy in 10 fractions(30 Gy/10f)of neoadjuvant radiotherapy(nRT).METHODS Three hundred and eighty-two patients with resectable and locally advanced rectal cancer were treated by 30 Gy/10f intermediate nRT(biologically equivalent dose of 36 Gy)plus total mesorectal excision.Two specimen fixation methods(FC or CF)were non-randomly used.The ypN0 status was identified in 124 and 101 patients in the FL and CF groups,respectively.Primary endpoints were local recurrence-free survival(LRFS)and cancer-specific survival(CSS).RESULTS The median follow-up of patients was 5.1 years.The median numbers of retrieved LNs in the FC and CF groups were 19.5(range,4-47)and 12(range,0-44),respectively,with a significant difference(P=0.000).The percentages of patients with 12 or more retrieved nodes were 82.3%and 50.5%(101/159)in the FC and CF groups,respectively,with a significant difference(P=0.000).The LRFS at 5 years were 95.7%and 94.6%in the FC and CF groups,respectively,without statistical difference(P=0.819).The CSS at 5 years were 92.0%and 87.2%in the FC and CF groups,respectively,without statistical difference(P=0.482).CONCLUSION For patients with ypN0 rectal cancer who underwent 30 Gy/10f preoperative radiotherapy,the increased retrieval of LNs using fat clearance is not associated with survival benefit.This time-consuming fixation method has a low efficacy as a routine practice.

Total neoadjuvant treatment for MRI-stratified high-risk rectal cancer:a single-center,single-arm,prospective Phase II trial(PKUCH-R02)

Background:Induction chemotherapy combined with neoadjuvant chemoradiotherapy has been recommended for patients with high-risk,locally advanced rectal cancer.However,the benefit of more intensive total neoadjuvant treatment(TNT)is unknown.This study aimed to assess the safety and efficacy of induction chemotherapy combined with chemoradiotherapy and consolidation chemotherapy for magnetic resonance imaging-stratified high-risk rectal cancer.Methods:This was a single-center,single-arm,prospective Phase II trial in Peking University Cancer Hospital(Beijing,China).Patients received three cycles of induction oxaliplatin and capecitabine(CapeOX)followed by chemoradiotherapy and two cycles of consolidation CapeOX.The primary end point was adverse event rate and the second primary end points were 3-year disease-free survival rate,completion of TNT,and pathological downstaging rate.Results:Between August 2017 and August 2018,68 rectal cancer patients with at least one high risk factor(cT3c/3d/T4a/T4b,cN2,mesorectal fascia involvement,or extramural venous invasion involvement)were enrolled.The overall compliance of receiving the entire treatment was 88.2%(60/68).All 68 patients received induction chemotherapy,65 received chemoradiotherapy,and 61 received consolidation chemotherapy.The Grade 3–4 adverse event rate was 30.8%(21/68).Nine patients achieved clinical complete response and then watch and wait.Five patients(7.4%)developed distant metastasis during TNT and received palliative chemotherapy.Fifty patients underwent surgical resection.The complete response rate was 27.9%.After a median follow-up of 49.2 months,the overall 3-year disease-free survival rate was 69.7%.Conclusions:For patients with high-risk rectal cancer,this TNT regimen can achieve favorable survival and complete response rates but with high toxicity.However,it is necessary to pay attention to the possibility of distant metastasis during the long treatment period.

Targeting KRAS G12C mutations in colorectal cancer

With the advent of Kirsten rat sarcoma viral oncogene homologue G12C(KRAS G12C)inhibitors,RAS is no longer considered undruggable.For the suppression of RAS,new therapeutic approaches have been suggested.However,current clinical studies have indicated therapeutic resistance after short-lived tumour suppression.According to preclinical studies,this might be associated with acquired genetic alterations,reactivation of downstream pathways,and stimulation for upstream signalling.In this review,we aimed to summarize current approaches for combination therapy to alleviate resistance to KRAS G12C inhibitors in colorectal cancer with a focus on the mechanisms of therapeutic resistance.We also analysed the relationship between various mechanisms and therapeutic resistance.

Organoid Culture of Isolated Cells from Patient-derived Tissues with Colorectal Cancer

Background：Colorectal cancer （CRC） is a heterogeneous disease;current research relies on cancer cell lines and animal cancer models,which may not precisely imitate inner human tumors and guide clinical medicine.The purpose of our study was to explore and further improve the process of producing three-dimensional （3D） organoid model and impel the development of personalized therapy.Methods：We subcutaneously injected surgically resected CRC tissues from a patient into BALB/c-nu mice to build patient-derived xenografts （PDXs）.Isolated cells from PDXs at appropriate tumor size were mingled with Matrigel,and then seeded in ultra-low attachment 96-well plates at four cell densities （500,1000,2000,and 4000 single cells/well）.Cells were cultured with advanced Dulbecco＇s Modified Eagle Mediurn/F 12 medium additional with various factors added to maintain tumor＇s biological traits and growth activity.The growth curves of the four cell densities were measured after 24 h of culture until 25 days.We evaluated the effects of four chemotherapeutic agents on organoid model by the CellTiter-Glo（R） Luminescent Cell Viability Assay.Hematoxylin and eosin （H and E） staining of 3D organoids was performed and compared with patient and CRC PDX tissues.Furthermore,immunohistochemistry was performed,in which the organoids were stained with the proliferation marker,Ki-67.During the experimental process,a phase-contrast microscope was used.Results：Phenotype experimental results showed that 3D organoids were tightly packed together and grew robustly over time.All four densities of cells formed organoids while that composed of 2000 cells/well provided an adequate cultivation system and grew approximately 8-fold at the 25th day.The chemosensitivity of the four conventional drugs was [s]-l 0-hydroxycamptothecin 〉 mitomycin C 〉 adriamycin 〉 paclitaxel,which can guide clinical treatment.Histological features of CRC patient＇s tumor tissues and mice tumor xenograft tissues were highly similar,with high-column-like epithelium and extracellular matrix.H and E-stained sections showed heterogeneous cell populations harbored in cancer organoids and were histologically similar to tumor tissues.The proliferation index was only 8.33% within spheroids,which exhibited confined proliferative cells that might be cancer stem cells.Conclusions：We successfully constructed a CRC organoid model that grew robustly over 25 days and demonstrated that 2000 cells/ well in 96-well plate was a prime seeding density for cells to form organoids.The results confirmed that organoid model can be used for agent screening and personalized medicine.

Organoid in colorectal cancer:progress and challenges

Patient-derived tumor organoids(PDOs)currently represent important modeling tools in pre-clinical investigation of malignancies.Organoid cultures conserve the genetic and phenotypic characteristics of the original tumor and maintain its heterogeneity,allowing their application in many research fields.PDOs derived from colorectal cancer(CRC)have been used for genetic modeling to investigate the function of driver genes.Some researchers have been exploring the value of CRC PDOs in chemotherapy,targeted therapy,and radiotherapy response prediction.The successful generation of PDOs derived from CRC could deepen our understanding of CRC biology and provide novel tools for cancer modeling,for realizing precision medicine by assessing specimens from individual patients ex vivo.The present review discusses recently reported advances in CRC PDOs and the challenges they face as pre-clinical models in CRC research.

Chinese guideline for the application of rectal cancer staging recognition systems based on artificial intelligence platforms (2021 edition)

Development and Application of Artificial Intelligence Recognition Systems in Rectal Cancer Staging Whether for surgical treatment or for neoadjuvant chemoradiotherapy,imaging evaluation has become an important basis to perform the treatment plans.[1]The reading of imaging results requires a large number of experienced radiologists to complete,but shortages and uneven distributions of personnel cause delays and biases in imaging results.Therefore,independent research and development of automatic recognition systems of rectal cancer staging based on artificial intelligence(AI)platforms aim to partially replace practitioners’work and achieve rapid and accurate identification of rectal cancer staging.