Evaluation of transrectal ultrasound-guided tru-cut biopsy as a complementary method for predicting pathological complete response in rectal cancer after neoadjuvant treatment: a phase II prospective and diagnostic trial.

IMPORTANCE: Patients with pCR of rectal cancer following neoadjuvant treatment had better oncological outcomes. However, reliable methods for accurately predicting pCR remain limited. OBJECTIVE: To evaluate whether transrectal ultrasound-guided tru-cut biopsy (TRUS-TCB) adds diagnostic value to conventional modalities for predicting pathological complete response (pCR) in patients with rectal cancer after neoadjuvant treatment. DESIGN, SETTING, AND PARTICIPANTS: This study evaluated data of patients with rectal cancer who were treated with neoadjuvant treatment and reassessed using TRUS-TCB and conventional modalities before surgery. This study is registered with ClinicalTrials.gov. MAIN OUTCOMES AND MEASURES: The primary outcome was accuracy, along with secondary outcomes including sensitivity, specificity, negative predictive value, and positive predictive value in predicting tumor residues. Final surgical pathology was used as reference standard. RESULTS: Between June 2021 and June 2022, a total of 74 patients were enrolled, with 63 patients ultimately evaluated. Among them, 17 patients (28%) exhibited a complete pathological response. TRUS-TCB demonstrated an accuracy of 0.71 (95% CI, 0.58-0.82) in predicting tumor residues. The combined use of TRUS-TCB and conventional modalities significantly improved diagnostic accuracy compared to conventional modalities alone (0.75 vs. 0.59, P=0.02). Furthermore, TRUS-TCB correctly reclassified 52% of patients erroneously classified as having a complete clinical response by conventional methods. The occurrence of only one mild adverse event was observed. CONCLUSIONS AND RELEVANCE: Transrectal ultrasound-guided tru-cut biopsy (TRUS-TCB) proves to be a safe and accessible tool for reevaluation with minimal complications. The incorporation of TRUS-TCB alongside conventional methods leads to enhanced diagnostic performance.

Electrostatic discharge induced degradation of optical-electrical properties and defect evolution of GaAs-based oxide-confined VCSELs.

GaAs-based oxide-confined vertical-cavity surface-emitting lasers (VCSELs) exhibit relatively low resistance against reliability-related damage. In order to gain a deeper understanding of the degradation and failure mechanism in oxide-confined VCSELs caused by electrostatic discharge (ESD)-induced defect proliferation, we investigated the effects of ESD stress on the degradation of optical-electrical characteristics and the evolution of defects in VCSELs under human body model test condition. The degradation threshold values for forward and reverse ESD pulse amplitudes were estimated to be 200 V and -50 V, respectively. Notably, VCSELs demonstrated greater sensitivity to reverse bias ESD compared to forward bias ESD. Analysis of optical emission and microstructure provided evidence that the device failure is attributed to an increase in ESD current density, leading to the multiplication of dark line defects (DLDs) originating from the edge of the device's oxide aperture. The formation of defects occurred suddenly in discrete events within small regions, rather than progressing gradually and uniformly. These defects propagated and led to damage across the entire active region. We believe that our results would be meaningful for improving the reliability of VCSEL in the future.

RNA demethylase ALKBH5 promotes colorectal cancer progression by posttranscriptional activation of RAB5A in an m6A-YTHDF2-dependent manner.

BACKGROUND: N6-methyladenosine (m6A) modification is an emerging epigenetic regulatory mechanism in tumourigenesis. Considering that AlkB homolog 5 (ALKBH5) is a well-described m6A demethylase in previous enzyme assays, we aimed to investigate the role of m6A methylation alteration conferred by disturbed ALKBH5 in colorectal cancer (CRC) development. METHODS: Expression of ALKBH5 and its correlation with clinicopathological characteristics of CRC were evaluated using the prospectively maintained institutional database. The molecular role and underlying mechanism of ALKBH5 in CRC were explored using in vitro and in vivo experiments with methylated RNA immunoprecipitation sequencing (MeRIP-seq), RNA-seq, MeRIP-qPCR, RIP-qPCR and luciferase reporter assays. RESULTS: ALKBH5 expression was significantly upregulated in CRC tissues compared to the paired adjacent normal tissues, and higher expression of ALKBH5 was independently associated with worse overall survival in CRC patients. Functionally, ALKBH5 promoted the proliferative, migrative and invasive abilities of CRC cells in vitro and enhanced subcutaneous tumour growth in vivo. Mechanistically, RAB5A was identified as the downstream target of ALKBH5 in CRC development, and ALKBH5 posttranscriptionally activated RAB5A by m6A demethylation, which impeded the YTHDF2-mediated degradation of RAB5A mRNA. In addition, we demonstrated that dysregulation of the ALKBH5-RAB5A axis could affect the tumourigenicity of CRC. CONCLUSIONS: ALKBH5 facilitates the progression of CRC by augmenting the expression of RAB5A via an m6A-YTHDF2-dependent manner. Our findings suggested that ALKBH5-RAB5A axis might serve as valuable biomarkers and effective therapeutic targets for CRC.

Clinical atlas of rectal cancer highlights the barriers and insufficient interventions underlying the unfavorable outcomes in older patients.

Background: Aging confers an increased risk of developing cancer, and the global burden of cancer is cumulating as human longevity increases. Providing adequate care for old patients with rectal cancer is challenging and complex. Method: A total of 428 and 44,788 patients diagnosed with non-metastatic rectal cancer from a referral tertiary care center (SYSU cohort) and the Surveillance Epidemiology and End Results database (SEER cohort) were included. Patients were categorized into old (over 65 years) and young (aged 50-65 years) groups. An age-specific clinical atlas of rectal cancer was generated, including the demographic and clinicopathological features, molecular profiles, treatment strategies, and clinical outcomes. Results: Old and young patients were similar in clinicopathological risk factors and molecular features, including TNM stage, tumor location, tumor differentiation, tumor morphology, lymphovascular invasion, and perineural invasion. However, old patients had significantly worse nutritional status and more comorbidities than young patients. In addition, old age was independently associated with less systemic cancer treatment (adjusted odds ratio 0.294 [95% CI 0.184-0.463, P < 0.001]). We found that old patients had significantly worse overall survival (OS) outcomes in both SYSU (P < 0.001) and SEER (P < 0.001) cohorts. Moreover, the death and recurrence risk of old patients in the subgroup not receiving chemo/radiotherapy (P < 0.001 for OS, and P = 0.046 for time to recurrence [TTR]) reverted into no significant risk in the subgroup receiving chemo/radiotherapy. Conclusions: Although old patients had similar tumor features to young patients, they had unfavorable survival outcomes associated with insufficient cancer care from old age. Specific trials with comprehensive geriatric assessment for old patients are needed to identify the optimal treatment regimens and improve unmet cancer care. Study registration: The study was registered on the research registry with the identifier of researchregistry 7635.

Neoadjuvant chemoradiotherapy versus neoadjuvant chemotherapy alone for patients with locally advanced rectal cancer: a propensity-score-matched analysis combined with SEER validation.

BACKGROUND: Neoadjuvant therapy followed by radical surgery is recommended for locally advanced rectal cancer (LARC). But radiotherapy can cause potential adverse effects. The therapeutic outcomes, postoperative survival and relapse rates between neoadjuvant chemotherapy (N-CT) and neoadjuvant chemoradiotherapy (N-CRT) patients have rarely been studied. METHODS: From February 2012 to April 2015, patients with LARC who underwent N-CT or N-CRT followed by radical surgery at our center were included. Pathologic response, surgical outcomes, postoperative complications and survival outcomes (including overall survival [OS], disease-free survival [DFS], cancer-specific survival [CSS] and locoregional recurrence-free survival [LRFS]) were analyzed and compared. Concurrently, the Surveillance, Epidemiology, and End Results Program (SEER) database was used to compare OS in an external source. RESULTS: A total of 256 patients were input into the propensity score-matching (PSM) analysis, and 104 pairs remained after PSM. After PSM, the baseline data were well matched and there was a significantly lower tumor regression grade (TRG) (P < 0.001), more postoperative complications (P = 0.009) (especially anastomotic fistula, P = 0.003) and a longer median hospital stay (P = 0.049) in the N-CRT group than in the N-CT group. No significant difference was observed in OS (P = 0.737), DFS (P = 0.580), CSS (P = 0.920) or LRFS (P = 0.086) between the N-CRT group and the N-CT group. In the SEER database, patients who received N-CT had similar OS in both TNM II (P = 0.315) and TNM III stages (P = 0.090) as those who received N-CRT. CONCLUSION: N-CT conferred similar survival benefits but caused fewer complications than N-CRT. Thus, it could be an alternative treatment of LARC.

Prevalent Pseudoprogression and Pseudoresidue in Patients With Rectal Cancer Treated With Neoadjuvant Immune Checkpoint Inhibitors.

BACKGROUND: Immune checkpoint inhibitor (ICI) treatment in patients with microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) tumors holds promise in reshaping organ preservation in rectal cancer. However, the benefits are accompanied by distinctive patterns of response, introducing a dilemma in the response evaluation for clinical decision-making. PATIENTS AND METHODS: Patients with locally advanced rectal cancer with MSI-H/dMMR tumors receiving neoadjuvant ICI (nICI) treatment (n=13) and matched patients receiving neoadjuvant chemoradiotherapy (nCRT; n=13) were included to compare clinical response and histopathologic features. RESULTS: Among the 13 patients receiving nICI treatment, in the final radiologic evaluation prior to surgery (at a median of 103 days after initiation of therapy), progressive disease (n=3), stable disease (n=1), partial response (n=7), and complete response (n=2) were observed. However, these patients were later confirmed as having pathologic complete response, resulting in pseudoprogression and pseudoresidue with incidences of 23.1% (n=3) and 76.9% (n=10), respectively, whereas no pseudoprogression was found in the 13 patients receiving nCRT. We further revealed the histopathologic basis underlying the pseudoprogression and pseudoresidue by discovering the distinctive immune-related regression features after nICI treatment, including fibrogenesis, dense lymphocytes, and plasma cell infiltration. CONCLUSIONS: Pseudoprogression and pseudoresidue were unique and prevalent response patterns in MSI-H/dMMR rectal cancer after nICI treatment. Our findings highlight the importance of developing specific strategies for response evaluation in neoadjuvant immunotherapy to identify patients with a good response in whom sphincter/organ-preserving or watch-and-wait strategies may be considered.

Clinical spectrum of rectal cancer identifies hallmarks of early-onset patients and next-generation treatment strategies.

BACKGROUND: The incidence of colorectal cancer is increasing among young adults and more rectal cancers are reported. This study aimed to identify the clinical features specific for early-onset rectal cancer and provide insights on cancer management. METHODS: Early-onset (<50 years) and late-onset (≥50 years) rectal cancer patients from a referral tertiary care center (SYSU cohort) and Surveillance Epidemiology and End Results database (SEER cohort) were included to perform a comprehensive comparison on clinical information. RESULTS: A total of 552 and 80,341 patients with stages I-III rectal cancer were included in the SYSU and SEER cohorts, respectively. In the SYSU cohort, early-onset diseases had significantly higher prevalence of family history of cancer and history of HBV infection and lower incidence of comorbidities (p < 0.05). In addition, early-onset patients presented more frequently with advanced node stage (N2 stage: 16.9 vs. 9.3%, p = 0.017) and high-risk features, including mucinous or signet cell carcinomas (21.8 vs. 12.9%, p = 0.014), poorly differentiated tumors (28.8 vs. 15.4%, p = 0.002), and perineural invasion (14.5 vs. 7.9%, p = 0.027) compared with late-onset patients. However, early-onset patients received more neoadjuvant (18.5 vs. 11.2%, p = 0.032) and adjuvant treatments (71.0 vs. 45.8%, p < 0.001), and they had better overall survival in both SYSU (HR 0.57, 95% CI: 0.34-0.95; p = 0.029) and SEER (HR 0.38, 95% CI: 0.37-0.40; p < 0.001) cohorts. CONCLUSION: Early-onset rectal cancers are distinct from late-onset cases in clinicopathological features, treatment modalities, and outcomes. The clinical trials and studies that are specific for young populations are needed to develop optimal strategies for cancer screening, treatment, and surveillance.

Current Surveillance After Treatment is Not Sufficient for Patients With Rectal Cancer With Negative Baseline CEA.

BACKGROUND: Serum CEA has been widely used to screen for potential recurrent disease after resection in rectal cancer. However, the influence of baseline CEA on the performance of CEA in recurrence surveillance needs to be investigated. PATIENTS AND METHODS: This longitudinal cohort study included 484 patients with nonmetastatic rectal cancer from 18,013 patients in a prospectively enrolled institutional database program of colorectal disease. Baseline CEA levels were determined before treatment, and CEA-based follow-up tests and examinations were applied in the surveillance after treatment. RESULTS: A total of 62.6% (62/99) overall, 53.5% (23/43) local, and 64.9% (50/77) distant recurrences were seen in patients who had similar CEA levels with their baseline statuses. The sensitivity of elevated CEA levels during surveillance for overall recurrence was significantly lower in patients with negative baseline CEA than in those with elevated baseline CEA levels (41.3% vs 69.4%; P =.007). Moreover, similar results were observed in the surveillance for local (50% vs 61.5%; P =.048) and distant (39.6% vs 72.4%; P =.005) recurrences between these 2 patient groups. However, CEA had comparable and excellent specificity during surveillance for recurrent disease in these groups. The addition of CA19-9 to the CEA assay significantly improved the sensitivity in recurrence surveillance for patients with negative baseline CEA (49.2% vs 41.3%; P =.037). Finally, we identified a subgroup of CEA-turn recurrences characterized by negative CEA at baseline, elevated CEA at recurrence, and worse survival outcomes after recurrence (hazard ratio, 1.88; 95% CI, 1.07-3.30; P =.026). CONCLUSIONS: In patients with rectal cancer with negative baseline CEA, serum CEA had insufficient sensitivity in recurrence surveillance after treatment, and additional surveillance may improve oncologic outcomes. Baseline CEA should be considered before CEA-based surveillance can be applied in the follow-up trials.

The Addition of Preoperative Radiation Is Insufficient for Lateral Pelvic Control in a Subgroup of Patients With Low Locally Advanced Rectal Cancer: A Post Hoc Study of a Randomized Controlled Trial.

BACKGROUND: The local recurrence of rectal cancer has been improved by total mesorectal excision following neoadjuvant chemoradiotherapy. However, in patients with low locally advanced rectal cancer, lateral pelvic recurrence remains to be addressed. OBJECTIVE: This study aimed to determine the efficiency of neoadjuvant radiotherapy in addressing lateral pelvic recurrence and which subgroup of patients might be optimal to receive lateral lymph node dissection. DESIGN: The MRI/CT images were reassessed for lateral lymph node status. The lateral lymph nodes with short axis ≥5 mm and ≥4 mm were considered positive in pretreatment and restaging MRI/CT. SETTING: This was a post hoc analysis of a prospective randomized controlled trial (FOWARC, NCT01211210). PATIENTS: A total of 495 patients with stage II or III rectal adenocarcinoma were included in the original trial. According to the excluding criteria, the finally included population consists of 253 patients; of these, 195 patients received neoadjuvant chemoradiotherapy and 94 received chemotherapy alone. MAIN OUTCOMES AND MEASURES: The primary outcome was the 5-year lateral pelvic recurrence rate. RESULTS: Compared with patients receiving chemotherapy alone, patients receiving additional radiotherapy had a marginal significance of lower lateral pelvic recurrence rate (6.6% vs 13.0%; p = 0.051). In the subset with pretreatment positive lateral lymph nodes, patients had a lateral pelvic recurrence rate of 22.6% and 45.1% after neoadjuvant chemoradiotherapy and chemotherapy alone. Of note, 34.9% of the pretreatment positive lateral lymph nodes were persistent after neoadjuvant chemoradiotherapy, culminating in a lateral pelvic recurrence rate of 63.3%. LIMITATIONS: This is a post hoc analysis, and only the patients from the leading center were included, which limited the sample size. In addition, the lateral lymph node dissection was not performed in this cohort. CONCLUSIONS: The addition of radiotherapy in neoadjuvant regimens could not address lateral pelvic recurrence adequately. Some subgroups of patients might need additional dissection. See Video Abstract at http://links.lww.com/DCR/B613. LA INCLUSION DE LA RADIOTERAPIA PREOPERATORIA ES INSUFICIIENTE EN EL CONTROL PLVICO LATERAL EN UN SUBGRUPO DE PACIENTES CON CNCER DE RECTO INFERIOR LOCALMENTE AVANZADO UN ESTUDIO POSTHOC CONTROLADO Y RANDOMIZADO: ANTECEDENTES:La recurrencia local del cancer de recto ha disminuido al efectuar una excision mesorrectal total seguida de quimioradioterapia neoadyuvante. No obstante, en pacientes con cancer de tercio inferior de recto avanzado localmente, aún está por controlarse la recurrencia pélvicaOBJETIVOS:Determinar la eficacia de la radioterapia neoadyuvante en el control de la recurrencia pélvica lateral y en que subgrupo de pacientes sería conveniente efecutar una excisión lateral de las cadenas ganglionares.DISEÑO:Se reevaluaron las imágenes tomográficas y de resonancia magnética del status de las cadenas ganglionares linfáticas laterales. Los ganglios linfáticos laterales con un eje-corto > 5 mm y ≥ 4 mm se consideraron como positivos previo al tratamiento y reestadificados con RM y TAC respectivamente.ESCENARIO:Es un análisis post hoc de un studio prospectivo randomizado controlado (FOWARC, NCT01211210).PACIENTESSe incluyeron un total de 495 pacientes en estdio II o III con adenomcarcinoma rectal en el estudio original. De acuerdo a los criterios de exclusión, la población final incluida consistió en 253 pacientes; de estos, 195 recibieron quimioradioterapia neoadyuvante y 94 quimioterapia sola.EVALUACION DE LOS RESULTADOS PRINCIPALES:El parámetro mas importante fue la tasa de recurrencia pélvica lateral a cinco años.RESULTADOS:En comparación con los pacientes que recibieron quimioterapia sola, aquellos que además fueron sometidos a radioterapia adicional presentaron un margen significativo de menor tasa de recurrencia pélvica lateral (6.6% vs. 13.0%; p=0.051). En el grupo de pacientes con ganglios linfáticos laterales positivos, los enfermos presentaron una tasa de recurrencia pélvica lateral de 22.6% y 45.1% después de quimioradiaterapia neoadyuvante en comparación con quimioterapia sola respectivamente. Cabe mencionar que el 34.9% de los pacientes con ganglios linfáticos laterales positivos antes del tratamiento persistieron después de la quimioradioterapia neoadyuvante, reportándose finalmente una recurrencia pélvica lateral de un 63.3%.LIMITACIONES:Se trata de un análisis posthoc y solo los pacientes del hospital fueron incluidos, lo que limita el tamaño de la muestra. Además, no se efectuó la disección de los ganglios linfáticos laterales en este grupo.CONCLUSIONES:La radioterapia en los esquemas de neoadyuvancia no logran controlar la recurrencia pélvica lateral en forma adecuada. Algunos subgrupos de pacientes podría requerir de disección adicional. Consulte Video Resumen en http://links.lww.com/DCR/B613.

eIF6 Promotes Colorectal Cancer Proliferation and Invasion by Regulating AKT-Related Signaling Pathways.

Although abnormal expression of eukaryotic initiation factor 6 (eIF6) has been found in several human solid tumors, the functions and underlying mechanisms of eIF6 in the progression of colorectal cancer (CRC) still needs further elucidation. In the present study, large-scale gene analysis based on Oncomine and The Cancer Genome Atlas (TCGA) database revealed significantly higher baseline expression of eIF6 in colorectal cancer than in normal tissues. Furthermore, our Chinese cohort study revealed that high expression of eIF6 was correlated with aggressive characteristics and poor survival in CRC patients. Functional studies using magnetic nanoparticle extraction indicated that eIF6 was an oncogene in CRC cells. Regarding its mechanism, through Gene ontology (GO) and KEGG pathway analysis based on TCGA RNAseq database, we found that eIF6 can activate multiple AKT-related cancer signaling pathways, such as p-AKT\MMP1\cyclinD1\Bcl2-related signaling, to regulate cell proliferation, invasion, cell cycle and apoptosis in CRC. Collectively, these findings suggested that eIF6 can positively regulate AKT-related cancer signaling and enhance tumorigenicity in CRC, and may serve as a potential prognostic indicator and therapeutic target in CRC.

Downregulation of phosphorylated MKK4 is associated with a poor prognosis in colorectal cancer patients.

Mitogen-activated protein kinase kinase 4 (MKK4) is a key mediator of Jun N-terminal kinase signaling and influences malignant metastasis. Here, we used immunohistochemistry to assess phosphorylated MMK4 (pMKK4) levels and examine their association with the clinicopathological features of a pilot set of patient samples consisting of normal colonic mucosa (NCM), colorectal adenoma (CA), and colorectal cancer (CRC) tissues. pMKK4 levels were also assessed in a validation set of CRC cases with accompanying follow-up data to confirm their clinicopathological and prognostic significance. pMKK4 levels, which were high in 79.17% of NCM samples, were downregulated in 33.33% of CA and 63.54% of CRC samples. pMKK4 downregulation was associated with metastasis, especially to the liver. In the validation set, pMKK4 downregulation was associated with increases in invasive depth, lymph node metastasis, distant metastasis, and TNM stage. Univariate analysis indicated that pMKK4 score, tumor differentiation, and TNM stage were correlated with disease-free survival and overall survival. Multivariate analysis indicated that decreased pMKK4 expression was an independent risk factor for disease-free survival in CRC patients. These results suggest that CRC patients with low pMKK4 immunochemistry scores should be monitored carefully for early detection of possible recurrences, especially liver metastasis.

Circadian Clock Gene CRY2 Degradation Is Involved in Chemoresistance of Colorectal Cancer.

Biomarkers for predicting chemotherapy response are important to the treatment of colorectal cancer patients. Cryptochrome 2 (CRY2) is a circadian clock protein involved in cell cycle, but the biologic consequences of this activity in cancer are poorly understood. We set up biochemical and cell biology analyses to analyze CRY2 expression and chemoresistance. Here, we report that CRY2 is overexpressed in chemoresistant colorectal cancer samples, and CRY2 overexpression is correlated with poor patient survival. Knockdown of CRY2 increased colorectal cancer sensitivity to oxaliplatin in colorectal cancer cells. We also identify FBXW7 as a novel E3 ubiquitin ligase for targeting CRY2 through proteasomal degradation. Mechanistic studies show that CRY2 is regulated by FBXW7, in which FBXW7 binds directly to phosphorylated Thr300 of CRY2. Furthermore, FBXW7 expression leads to degradation of CRY2 through enhancing CRY2 ubiquitination and accelerating the CRY2's turnover rate. High FBXW7 expression downregulates CRY2 and increases colorectal cancer cells' sensitivity to chemotherapy. Low FBXW7 expression is correlated with high CRY2 expression in colorectal cancer patient samples. Also, low FBXW7 expression is correlated with poor patient survival. Taken together, our findings indicate that the upregulation of CRY2 caused by downregulation of FBXW7 may be a novel prognostic biomarker and may represent a new therapeutic target in colorectal cancer.

Phosphorylated p38, a negative prognostic biomarker, complements TNM staging prognostication in colorectal cancer.

Phosphorylated p38 (p-p38) played a pivotal role in the regulation of disease progression and correlated with tumor prognosis. Here, we characterized the prognostic effect of p-p38 in colorectal cancer (CRC). Three hundred and sixteen CRC patients in stages I-III were recruited in this study. P-p38 expression was semi-quantitatively evaluated using tissue microarrays and immunohistochemistry staining. Overall survival (OS), disease-free survival (DFS), local failure-free survival (LFFS), and distant metastasis-free survival (DMFS) of patient subgroups, segregated by p-p38 expression level and clinical stage, were compared using Kaplan-Meier analysis. We found that p-p38 was overexpressed in 48.1 % (152/316) CRC tissues, whereas low or deficiently expressed in normal adjacent epithelia. Overexpression of p-p38 predicted poor OS (P < 0.001), DFS (P = 0.002), LFFS (P = 0.016), and DMFS (P = 0.025) in CRC. Importantly, patient subgroups in the early stage (stages I + II) and with low p-p38 had similar OS, PFS, LFFS, and DMFS probabilities to that of stage I, whereas those with high p-p38 were similar to stage III disease. In addition, for stage III disease, the subgroup with low p-p38 had a similar survival probability to that of stage I, whereas the subgroup with high p-p38 had the worst survival. Multivariate Cox analysis confirmed that p-p38 was indeed a significantly independent factor for death, recurrence, and distant metastases in CRC. Our results demonstrated that p-p38 was a negative independent prognostic factor for CRC. Complementing TNM staging with p-p38 might refine the risk definition more accurately for a subset of patients.

Overexpression of MEKK2 is associated with colorectal carcinogenesis.

Mitogen-activated protein kinase kinase kinase 2 (MEKK2) is an important upstream mediator of the extracellular signal-regulated kinase 5 signaling cascade that is essential for a number of cellular functions, including mitogenesis, differentiation and oncogenic transformation. Using western blotting to examine MEKK2 expression in 16 cases of primary colorectal cancer (CRC) lesions with paired normal mucosa, it was identified that MEKK2 is highly expressed in CRC lesions compared with that of the normal mucosa. Immunohistochemistry of 24 normal mucosa, 24 adenoma and 96 adenocarcinoma colorectal specimens indicated that the expression of MEKK2 was significantly increased in the adenoma and carcinoma specimens compared with that of the normal mucosa cases (P<0.0001 for both). However, no significant differences were detected in MEKK2 expression between the carcinoma and adenoma specimens (P=0.85). Similarly, no correlations were identified between MEKK2 expression and clinicopathological features, including gender, age, body mass index, histological differentiation, depth of invasion, lymph node metastasis, UICC stage and K-ras mutations (P>0.05). The present study demonstrated that MEKK2 functions as a promotive factor in CRC.

[Expression and clinicopathological significance of serine-257/threonine-261 phosphorylated MKK4 in colorectal carcinoma].

OBJECTIVE: As an activator of JNK and p38, phosphorylated MKK4 is considered to be associated with tumor progression and prognosis. This study was to examine the expression of pMKK4 and evaluate its prognostic significance in colorectal carcinoma. METHODS: A total of 343 cases of colorectal cancer were followed up to analyze the associations between the expression of pMKK4 and various clinicopathological factors. The expression of Serine-257/Threonine-261 pMKK4 was detected immunohistochemically by tissue microarray. RESULTS: The staining of pMKK4 was present in cytoplasm of colorectal carcinoma. And the expression of pMKK4 was correlated with invasion depth (P = 0.003), differentiation (P = 0.018), lymph node metastasis (P < 0.001), metastasis (P < 0.001), hepatic metastasis (P = 0.039) and TNM stage (P < 0.001). The patients with strong pMKK4 staining had a better overall survival than those with lowered levels (Log rank = 4.531, P = 0.033). Univariate analysis indicated that the expression of pMKK4 was correlated with either overall survival (HR = 0.785, P = 0.035) or relapse-free survival (HR = 0.788, P = 0.044). In multivariate analysis, there was no prognostic significance of pMKK4 after adjusting for invasion depth, differentiation, lymph node metastasis, metastasis, liver metastasis and TNM stage. CONCLUSIONS: The down-regulation of S257/T261 pMKK4 is associated with more advanced stages and it plays an important role in tumor progression. A high-level expression of pMKK4 indicates favorable clinical outcomes, but it is not an independent predictor.

Screening for differentially methylated genes among human colorectal cancer tissues and normal mucosa by microarray chip.

UNLABELLED: High density DNA methylation microarrays were used to study the differences of gene methylation level in six pairs of colorectal cancer (CRC) and adjacent normal mucosa. We analyzed the profile of methylated genes by NimbleGen Microarray and the biologic functions by NIH-NAVID. In addition, preliminary validation studies were done in six pairs of samples by MSP (methylation-specific PCR). A total of 4,644 genes had a difference in methylation levels. Among them 2,296 were hypermethylated (log2ratio > 1), 2,348 genes were hypomethylated (log2ratio < -1), in which 293 hypermethylated and 313 hypomethylated genes were unmapped according to the NIH-NAVID. All these genes were randomly distributed on all the chromosomes. However, chromosome 1 contained the most of the hypermethylated genes (232 genes), followed by chromosome 19 (149 genes), chromosome 11 (144 genes), chromosome 2 (141 genes), chromosomes 3 (127 genes). Through the analysis of the statistics, There were 2 hypermethylated/3 hypomethylated genes involved in six pairs of samples simultaneously, followed by 10/14 in five samples, 34/37 in four samples, 101/113 in three samples, 341/377 in two samples, 1,808/1,804 in one sample. According to gene ontology analysis, some physiological processes play important roles in the cell division and the development of tumor, such as apoptosis, DNA repair, immune, cell cycle, cell cycle checkpoint, cell adhesion and invasion etc. Through Preliminary validation, there were two genes (St3gal6, Opcml) in thirty top-ranking genes shown hypermethylated in six pairs of CRC and adjacent normal mucosa. CONCLUSIONS: High density DNA methylation microarrays is an effective method for screening aberrantly methylated genes in CRC. The methylated genes should be further studied for diagnostic or prognostic markers for CRC.