SMAD4 gene mutation predicts poor prognosis in patients undergoing resection for colorectal liver metastases. Eur J Surg Oncol. 2018;44:684-692. [PMID: 29551247 DOI: 10.1016/j.ejso.2018.02.247]

Coaltered Ras/B-raf and TP53 Is Associated with Extremes of Survivorship and Distinct Patterns of Metastasis in Patients with Metastatic Colorectal Cancer

PURPOSE

We aimed to investigate genomic correlates underlying extremes of survivorship in metastatic colorectal cancer and their applicability in informing survival in distinct subsets of patients with metastatic colorectal cancer.

EXPERIMENTAL DESIGN

We examined differences in oncogenic somatic alterations between metastatic colorectal cancer cohorts demonstrating extremes of survivorship following complete metastasectomy: ≤2-year (n = 17) and ≥10-year (n = 18) survivors. Relevant genomic findings, and their association with overall survival (OS), were validated in two independent datasets of 935 stage IV and 443 resected stage I-IV patients.

RESULTS

In the extremes-of-survivorship cohort, significant co-occurrence of KRAS hotspot mutations and TP53 alterations was observed in ≤2-year survivors (P < 0.001). When validating these findings in the independent cohort of 935 stage IV patients, incorporation of the cumulative effect of any oncogenic Ras/B-raf (i.e., either KRAS, NRAS, or BRAF) and TP53 alteration generated three prognostic clusters: (i) TP53-altered alone (median OS, 132 months); (ii) Ras/B-raf-altered alone (65 months) or Ras/B-raf- and TP53 pan-wild-type (60 months); and (iii) coaltered Ras/B-raf-TP53 (40 months; P < 0.0001). Coaltered Ras/B-raf-TP53 was independently associated with mortality (HR, 2.47; 95% confidence interval, 1.91-3.21; P < 0.001). This molecular profile predicted survival in the second independent cohort of 443 resected stage I-IV patients. Coaltered Ras/B-raf-TP53 was associated with worse OS in patients with liver (n = 490) and lung (n = 172) but not peritoneal surface (n = 149) metastases. Moreover, coaltered Ras/B-raf-TP53 tumors were significantly more likely to involve extrahepatic metastatic sites with limited salvage options.

CONCLUSIONS

Genomic analysis of extremes of survivorship following colorectal cancer metastasectomy identifies a prognostic role for coaltered Ras/B-raf-TP53 and its association with distinct patterns of colorectal cancer metastasis.

Genomic stratification beyond Ras/B-Raf in colorectal liver metastasis patients treated with hepatic arterial infusion

Background

Resection of colorectal liver metastases (CLM) can cure disease, but many patients with extensive disease cannot be fully resected and others recur following surgery. Hepatic arterial infusion (HAI) chemotherapy can convert extensive liver disease to a resectable state or decrease recurrence risk, but response varies and no biomarkers currently exist to identify patients most likely to benefit.

Methods

We performed a retrospective cohort study of CLM patients receiving HAI chemotherapy whose tumors underwent MSK‐IMPACT sequencing. The frequency of oncogenic alterations and their association with overall survival (OS) and objective response rate were analyzed at the individual gene and signaling pathway levels.

Results

Three hundred and seventy patients met inclusion criteria: 189 (51.1%) who underwent colorectal liver metastasectomy followed by HAI + systemic therapy (Adjuvant cohort), and 181 (48.9%) with unresectable CLM (Metastatic cohort) who received HAI + systemic therapy, consisting of 63 (34.8%) with extrahepatic disease and 118 (65.2%) with liver‐restricted disease. Genomic alterations were similar in each cohort, and no individual gene or pathway was significantly associated with objective response. Patients in the adjuvant cohort with concurrent Ras/B‐Raf alteration and SMAD4 inactivation had worse prognosis while in the metastatic cohort patients with co‐alteration of Ras/B‐Raf and TP53 had worse OS. Similar findings were observed in a validation cohort.

Conclusions

Concurrently altered Ras/B‐Raf and SMAD4 mutations were associated with worse survival in resectable patients, while concurrent Ras/B‐Raf and TP53 alterations were associated with worse survival in unresectable patients. The mutual exclusivity of Ras/B‐Raf, SMAD4, and TP53 may have prognostic value for CLM patients receiving HAI.

Eribulin rapidly inhibits TGF-β-induced Snail expression and can induce Slug expression in a Smad4-dependent manner

Background

Evidence shows that the anticancer effects of microtubule targeting agents are not due solely to their antimitotic activities but also their ability to impair microtubule-dependent oncogenic signalling.

Methods

The effects of microtubule targeting agents on regulators of TGF-β-induced epithelial-to-mesenchymal transition (EMT) were evaluated in breast cancer cell lines using high content imaging, gene and protein expression, siRNA-mediated knockdown and chromatin immunoprecipitation.

Results

Microtubule targeting agents rapidly and differentially alter the expression of Snail and Slug, key EMT-promoting transcription factors in breast cancer. Eribulin, vinorelbine and in some cases, ixabepalone, but not paclitaxel, inhibited TGF-β-mediated Snail expression by impairing the microtubule-dependent nuclear localisation of Smad2/3. In contrast, eribulin and vinorelbine promoted a TGF-β-independent increase in Slug in cells with low Smad4. Mechanistically, microtubule depolymerisation induces c-Jun, which consequently increases Slug expression in cells with low Smad4.

Conclusion

These results identify a mechanism by which eribulin-mediated microtubule disruption could reverse EMT in preclinical models and in patients. Furthermore, high Smad4 levels could serve as a biomarker of this response. This study highlights that microtubule targeting drugs can exert distinct effects on the expression of EMT-regulating transcription factors and that identifying differences among these drugs could lead to their more rational use.

Gene mutation and surgical technique: Suggestion or more?

Advancements in chemotherapy and molecular targeted therapy have improved long-term outcomes for patients with resectable colorectal liver metastases (CLM). RAS mutation status was an original focus as a molecular biomarker as it predicted treatments response to anti-epidermal growth factor receptor agents. More recently, studies have incorporated somatic mutation data in analyses pertaining to surgical outcomes and prognosis. This evidenced-based review covers the implications of somatic mutations in patients undergoing resection of CLM.

Mutation Status of RAS, TP53, and SMAD4 is Superior to Mutation Status of RAS Alone for Predicting Prognosis after Resection of Colorectal Liver Metastases

PURPOSE

Somatic gene mutations have been increasingly recognized to impact prognosis following resection of colorectal liver metastases (CLM). We aimed to determine the impact of combinations of somatic mutations on survival in patients undergoing CLM resection.

EXPERIMENTAL DESIGN

We identified patients who underwent initial CLM resection during 2007-2017 and had genetic sequencing data available. Risk factors for overall survival (OS) and recurrence-free survival (RFS) were determined using Cox proportional hazards models.

RESULTS

Of 1460 patients who underwent CLM resection during the study period, 507 met the inclusion criteria. Multigene testing revealed mutation rates greater than 10% for TP53 (mutated in 70.8% of patients), APC (53.5%), RAS (50.7%), PIK3CA (15.8%), and SMAD4 (11.0%). BRAF was mutated in 2.0% of patients. BRAF, RAS, TP53, and SMAD4 mutations were significantly associated with OS, and RAS, TP53, and SMAD4 mutations were significantly associated with RFS. Coexisting mutations in RAS, TP53, and SMAD4 were associated with significantly worse OS and RFS than coexisting mutations in any 2 of these genes and mutations in 1 or none of these genes. Coexisting mutations in 2 genes conferred significantly worse OS and RFS than single mutation or no mutations. OS and RFS did not differ significantly between patients with RAS mutation and wild-type TP53 and SMAD4 and patients with wild-type RAS (P = 0.858 and 0.729, respectively).

CONCLUSIONS

RAS mutation status alone is not sufficient for precisely predicting prognosis after CLM resection.

Elevated expression of CXCL16 correlates with poor prognosis in patients with colorectal cancer

Aims: To examine the expression of CXCL16 in colorectal cancer (CRC) tissue and to clarify the relationships between CXCL16 and clinicopathological features and survival in CRC.

Methods: A total of 142 consecutive CRC patients undergoing colorectal surgery at the Department of Gastrointestinal Center, First Affiliated Hospital, Sun Yat-sen University, between January 2010 and December 2010 were enrolled in this study. CXCL16 was measured by immunohistochemical staining in CRC tissue. Association between CXCL16 expression and clinicopathologic parameters was analyzed with a chi-square test. Survival curves were calculated by the Kaplan–Meier method, and the differences between CXCL16 high- and low-expression groups were analyzed using the log-rank test. Cox univariate and multivariate analyses were used to determine risk factors for overall survival (OS).

Results: CXCL16 expression was elevated in CRC. CXCL16-positive expression was significantly related to tumor size (P=0.043), tumor differentiation (P=0.046) and distant metastasis (P=0.038), and there was a trend toward lymph node metastasis (P=0.070). CXCL16 expression, together with differentiation, depth of invasion, lymph node metastasis, and distant metastasis, was a significant independent prognostic factor for OS of patients with CRC (HR 2.026, 95% CI 1.128–3.640, P=0.018).

Conclusion: CXCL16 expression was enhanced in CRC tissue and was negatively correlated with survival in CRC patients. Furthermore, CXCL16-positive expression was an independent prognostic factor for CRC patients, whilst the underlying mechanisms remain unclear; thus, further studies are needed.

miRNA and mRNA Integration Network Construction Reveals Novel Key Regulators in Left-Sided and Right-Sided Colon Adenocarcinoma

Background

The distinction between right-sided and left-sided colon adenocarcinoma has recently received considerable. This study aims to identify key MicroRNA (miRNA) and mRNAs in right-sided colon adenocarcinoma (RSCOAD) and left-sided colon adenocarcinoma (LSCOAD) by TCGA integration analysis.

Methods

The miRNA and mRNA expression profiles of a large group of patients with RSCOAD and LSCOAD were obtained from TCGA. The differentially expressed miRNAs (DEmiRNAs) and mRNAs (DEmRNAs) were identified by TCGA integration analysis. The optimal diagnostic miRNA biomarkers for RSCOAD and LSCOAD were identified by Boruta algorithm. We established classification models to distinguish RSCOAD and LSCOAD. Protein-protein interaction (PPI) network analysis, DEmiRNA-DEmRNA interaction analysis, and functional annotation were performed. The expression of selected DEmiRNAs and DEmRNAs was validated by qRT-PCR.

Results

A total of 2534 DEmRNAs (940 downregulated and 1594 upregulated mRNAs) and 54 DEmiRNAs (22 downregulated and 32 upregulated miRNAs) between RSCOAD and LSCOAD were identified. The feature selection procedure was to obtain 22 optimal diagnostic miRNAs biomarkers in RSCOAD compared to LSCOAD. The AUC of the random forests model was 0.869 and the specificity and sensitivity of this model were 79% and 84.6%, respectively. Three DEmiRNAs (hsa-miR-224-5p, hsa-miR-155-5p, and hsa-miR-31-5p) and five DEmRNAs (CXCR4, SMAD4, KRAS, FITM2, and PLAGL2) were identified key DEmiRNAs and DEmRNAs in RSCOAD compared to LSCOAD. The qRT-PCR results of CXCR4, FITM2, TFAP2A, ULBP2, hsa-miR-224-5p, and hsa-miR-155-5p were consistent with our integrated analysis.

Conclusion

A total of three DEmiRNAs (hsa-miR-224-5p, hsa-miR-155-5p, and hsa-miR-31-5p) and five DEmRNAs (CXCR4, SMAD4, KRAS, FITM2, and PLAGL2) may be involved in the pathogenesis of RSCOAD and LSCOAD which may make a contribution for understanding mechanisms and developing therapeutic strategies for RSCOAD and LSCOAD.

Clinicopathological characterization of SMAD4-mutated intestinal adenocarcinomas: A case-control study

The SMAD4 tumor suppressor gene product inhibits transforming growth factor-β-mediated signaling and is mutated in ~10% of colorectal carcinomas. The prognostic significance of SMAD4 mutations has been controversial. We studied the pathological and clinical characteristics of SMAD4-mutated intestinal adenocarcinomas using a retrospective case-control study design. Cases and controls were identified among 443 primary adenocarcinomas that had undergone next generation DNA sequencing (NGS) with the Ion AmpliSeq Cancer Hotspot Panel v2, which evaluates 50 cancer-related genes. Twenty-eight SMAD4-mutated (SMAD4m) patients were matched 1:2 with 56 consecutive SMAD4 wild-type (SMAD4wt) control patients from the same analysis stream. Compared with the SMAD4wt controls, the SMAD4m tumors were of higher stage (P = 0.026) and were more likely to feature mucinous differentiation (P = 0.0000), to occur in the setting of Crohn’s disease (P = 0.0041), and to harbor concurrent RAS mutations (P = 0.0178). Tumor mucin content was significantly correlated with mutations involving the MH2 domain of the SMAD4 protein (P = 0.0338). Correspondence between mutation sites and morphology was demonstrated directly in a mixed adenocarcinoma and neuroendocrine tumor where SMAD4 mutations involving different protein domains were found in histologically disparate tumor regions despite both containing identical KRAS and TP53 mutations.

Back to the Colorectal Cancer Consensus Molecular Subtype Future

PURPOSE OF REVIEW

This review seeks to provide an informed prospective on the advances in molecular profiling and analysis of colorectal cancer (CRC). The goal is to provide a historical context and current summary on how advances in gene and protein sequencing technology along with computer capabilities led to our current bioinformatic advances in the field.

RECENT FINDINGS

An explosion of knowledge has occurred regarding genetic, epigenetic, and biochemical alterations associated with the evolution of colorectal cancer. This has led to the realization that CRC is a heterogeneous disease with molecular alterations often dictating natural history, response to treatment, and outcome. The consensus molecular subtypes (CMS) classification classifies CRC into four molecular subtypes with distinct biological characteristics, which may form the basis for clinical stratification and subtype-based targeted intervention. This review summarizes new developments of a field moving "Back to the Future." CRC molecular subtyping will better identify key subtype specific therapeutic targets and responses to therapy.

Epithelial–Mesenchymal Transition Induced by SMAD4 Activation in Invasive Growth Hormone-Secreting Adenomas

Background

The detection and treatment of invasive growth hormone-secreting pituitary adenoma (GHPA) remains challenging. Several transcription factors promoting the epithelial–mesenchymal transition (EMT) can act as cofactors for the transforming growth factor-beta (TGF-ß)/SMAD4. The goal of this study was to investigate the association of SMAD4 expression and clinicopathologic features using a tissue microarray analysis (TMA). The levels of SMAD4 and the related genes of EMT in GHPAs were analyzed by q-PCR and western blot. SMAD4 was strongly expressed in 15/19 cases (78.9%) of invasive GHPA and 10/42 cases (23.8%) of noninvasive GHPA (χ2=10.887,p=0.000). In the high SMAD4 group, a headache was reported in 16/25 cases (64%) compared with 13/36 cases (36.1%) in the low SMAD4 group (χ2=4.565,p=0.032). The progression-free survival (PFS) in the high group was lower than that in the low group (p=0.026). qRT-PCR and western blot analysis further revealed a significant downregulation of E-cadherin and upregulation of N-cadherin and vimentin in the invasive GHPA group. SMAD4 was associated with increased levels of invasion of GH3 cells, as determined by a transwell test. SMAD4 downregulated E-cadherin levels and increased the levels of N-cadherin and vimentin. Our data provide evidence that SMAD4 is a potential prognosis biomarker and a therapeutic target for patients with invasive GHPA.