Mutations in TP53 are a prognostic factor in colorectal hepatic metastases undergoing surgical resection

Somatic Mutations in Surgically Treated Colorectal Liver Metastases: An Overview

Colorectal cancer is the second most common cause of cancer death in the United States, and up to half of patients develop colorectal liver metastases (CRLMs). Notably, somatic genetic mutations, such as mutations in RAS, BRAF, mismatch repair (MMR) genes, TP53, and SMAD4, have been shown to play a prognostic role in patients with CRLM. This review summarizes and appraises the current literature regarding the most relevant somatic mutations in surgically treated CRLM by not only reviewing representative studies, but also providing recommendations for areas of future research. In addition, advancements in genetic testing and an increasing emphasis on precision medicine have led to a more nuanced understanding of these mutations; thus, more granular data for each mutation are reviewed when available. Importantly, such knowledge can pave the way for precision medicine with the ultimate goal of improving patient outcomes.

Optimal patient selection for successful two-stage hepatectomy of bilateral colorectal liver metastases

Two-stage hepatectomy (TSH) is one of the specific surgical techniques that can expand the pool of resectable patients with initially unresectable colorectal liver metastases (CRLM). The indication of TSH for CRLM is only bilateral, multinodular disease, which cannot be resected by a single hepatectomy. TSH is nowadays considered an effective treatment for selected patients, with acceptable morbidity/mortality rates and promising long-term outcomes. However, not all eligible patients can benefit from the TSH strategy. One of the most important issues is dropout from the strategy (failure to complete both of the two sequential procedures), because the survival of such patients is drastically worse compared with patients who can complete both stages. Another important issue is the early recurrence rate and subsequent poor survival even after completion of TSH. Thus, the selection of appropriate patients who can really benefit from the TSH strategy is crucial. This review discusses the optimal patient selection for TSH, which should be helpful for the development of treatment strategies for patients with extensive CRLM.

Genetic mutations associated with sensitivity to neoadjuvant chemotherapy in metastatic colon cancer: A case report and review of literature

BACKGROUND

Colorectal liver metastases (CLM) occur in 15%-30% of patients with colorectal cancer (CRC). Advancements in next generation sequencing (NGS) can provide more precise prognoses for cancer patients and help guide clinical treatment. However, the genetic variants that predict high sensitivity to neoadjuvant chemotherapy remain unclear, especially in patients with CLM. The aim of this study was to identify the relevant genetic variants in a single CLM patient and to summarize the current evidence on mutations and single nucleotide polymorphisms (SNPs) that objectively predict sensitivity to neoadjuvant chemotherapy.

CASE SUMMARY

A 76-year-old male patient, who was diagnosed as stage IV colon cancer with liver metastases, was found to have APC/TP53/KRAS mutations. He showed a good therapeutic response to 12 courses of oxaliplatin regimens combined with Bevacizumab. Genetic analysis of the patient identified 5 genes with 7 detected SNPs that may be related to a better response to chemotherapy drugs. In addition, a critical literature review was performed based on a standardized appraisal form after selecting the articles. Ultimately, 21 eligible studies were appraised to assess the association between gene mutations and good prognosis. Mutations in KRAS, TP53, SMAD4, and APC were identified as being associated with a poor response to chemotherapy drugs, whereas mutations of CREBBP and POLD1 were associated with longer overall survival.

CONCLUSION

NGS can identify precise predictors of response to neoadjuvant chemotherapy, leading to improved outcomes for CRC patients.

The Interactions of DNA Repair, Telomere Homeostasis, and p53 Mutational Status in Solid Cancers: Risk, Prognosis, and Prediction

The disruption of genomic integrity due to the accumulation of various kinds of DNA damage, deficient DNA repair capacity, and telomere shortening constitute the hallmarks of malignant diseases. DNA damage response (DDR) is a signaling network to process DNA damage with importance for both cancer development and chemotherapy outcome. DDR represents the complex events that detect DNA lesions and activate signaling networks (cell cycle checkpoint induction, DNA repair, and induction of cell death). TP53, the guardian of the genome, governs the cell response, resulting in cell cycle arrest, DNA damage repair, apoptosis, and senescence. The mutational status of TP53 has an impact on DDR, and somatic mutations in this gene represent one of the critical events in human carcinogenesis. Telomere dysfunction in cells that lack p53-mediated surveillance of genomic integrity along with the involvement of DNA repair in telomeric DNA regions leads to genomic instability. While the role of individual players (DDR, telomere homeostasis, and TP53) in human cancers has attracted attention for some time, there is insufficient understanding of the interactions between these pathways. Since solid cancer is a complex and multifactorial disease with considerable inter- and intra-tumor heterogeneity, we mainly dedicated this review to the interactions of DNA repair, telomere homeostasis, and TP53 mutational status, in relation to (a) cancer risk, (b) cancer progression, and (c) cancer therapy.

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.

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.

Conditional Recurrence-Free Survival after Resection of Colorectal Liver Metastases: Persistent Deleterious Association with RAS and TP53 Co-Mutation

BACKGROUND

Conditional recurrence-free survival (RFS) probability, that is, the probability of remaining recurrence-free after a given interval without recurrence, has not been reported after resection of colorectal liver metastases (CLMs). We aimed to estimate conditional RFS and identify factors affecting conditional RFS.

STUDY DESIGN

Patients undergoing initial resection of CLMs during 2000-2016 with mutation data were identified. The RFS and risk factors for recurrence were evaluated at the time of resection for all patients and at 1 year and 2 years after resection for patients who remained recurrence-free.

RESULTS

Of 2,118 patients, 485 met the inclusion criteria, of which 225 were recurrence-free at 1 year and 109 were recurrence-free at 2 years. The 5-year RFS rates were 17.3%, 36.8%, and 70.7% for all patients and the 1-year and 2-year recurrence-free groups, respectively, when assessed from the time of initial CLM resection. RAS/TP53 co-mutation was the only factor independently associated with increased risk of recurrence for all groups (all patients, hazard ratio 1.47; 95% CI 1.19 to 1.82; p < 0.001; 1-year recurrence-free, hazard ratio 1.69; 95% CI 1.17 to 2.43; p = 0.005; 2-year recurrence-free, hazard ratio 2.41; 95% CI 1.12 to 5.17; p = 0.024). T category, extrahepatic disease, multiple CLMs, largest CLM diameter, and surgical margin status were risk factors for recurrence in all patients and/or the 1-year recurrence-free group, but not the 2-year recurrence-free group. Median RFS was lower for patients with RAS/TP53 co-mutation than for those with RAS/TP53 wild-type in the 1-year (1.5 vs 2.8 years; p = 0.006) and 2-year recurrence-free groups (3.0 vs 5.9 years; p = 0.024).

CONCLUSIONS

Conditional RFS is useful for updating prognosis after a given time interval without recurrence after CLM resection. Importantly, RAS/TP53 co-mutation has a persistent deleterious association with recurrence.

Biomarker concordance between primary colorectal cancer and its metastases

Background

The use of biomarkers to target anti-EGFR treatments for metastatic colorectal cancer (CRC) is well-established, requiring molecular analysis of primary or metastatic biopsies. We aim to review concordance between primary CRC and its metastatic sites.

Methods

A systematic review and meta-analysis of all published studies (1991–2018) reporting on biomarker concordance between primary CRC and its metastatic site(s) was undertaken according to PRISMA guidelines using several medical databases. Studies without matched samples or using peripheral blood for biomarker analysis were excluded.

Findings

61 studies including 3565 patient samples were included. Median biomarker concordance for KRAS (n = 50) was 93.7% [[67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92], [93], [94], [95], [96], [97], [98], [99], [100]], NRAS (n = 11) was 100% [[90], [91], [92], [93], [94], [95], [96], [97], [98], [99], [100]], BRAF (n = 22) was 99.4% [[80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92], [93], [94], [95], [96], [97], [98], [99], [100]], and PIK3CA (n = 17) was 93% [[42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92], [93], [94], [95], [96], [97], [98], [99], [100]]. Meta-analytic pooled discordance was 8% for KRAS (95% CI = 5–10%), 8% for BRAF (95% CI = 5–10%), 7% for PIK3CA (95% CI = 2–13%), and 28% overall (95% CI = 14–44%). The liver was the most commonly biopsied metastatic site (n = 2276), followed by lung (n = 438), lymph nodes (n = 1123), and peritoneum (n = 132). Median absolute concordance in multiple biomarkers was 81% (5–95%).

Interpretation

Metastatic CRC demonstrates high concordance across multiple biomarkers, suggesting that molecular testing of either the primary or liver and lung metastasis is adequate. More research on colorectal peritoneal metastases is required.

Immunohistochemical investigation of prognostic biomarkers in resected colorectal liver metastases: a systematic review and meta-analysis

Background

Many studies have investigated the prognostic role of biomarkers in colorectal liver metastases (CRLM). However, no biomarker has been established in routine clinical practice. The aim of this study was to scrutinize the current literature for biomarkers evaluated by immunohistochemistry as prognostic markers in patients with resected CRLM.

Methods

A systematic review was performed according to the PRISMA guidelines. Articles were identified in the PubMed database with selected search terms and by cross-references search. The REMARK quality criteria were applied. Markers were included if they reported the prognostic impact of immunohistochemical markers in a multivariable setting in relation to overall survival (OS). A meta-analysis was conducted when more than one original article provided survival data of a marker.

Results

In total, 26 biomarkers were identified as independent significant markers for OS in resected CRLM. These biomarkers were found to be involved in multiple oncogenic signalling pathways that control cell growth, apoptosis, angiogenesis and evasion of immune detection. Among these biomarker candidates were Ki-67, EGFR, p53, hTERT, CD34, TSP-1, KISS1, Aurora kinase A and CDX2. CD34 and TSP-1 were reported as significantly associated with survival by more than one study and where therefore pooled in a meta-analysis.

Conclusion

A number of independent prognostic biomarkers for resected CRLM were identified. However, most markers were evaluated in a retrospective setting with small patient cohorts, without external validation. Large, prospective, multicentre studies with standardised methods are needed before biomarkers can translated into the clinic.

Biomarkers in colorectal liver metastases

BACKGROUND

Despite a 5-year overall survival rate of 58 per cent after liver resection for colorectal liver metastases (CLMs), more than half of patients develop recurrence, highlighting the need for accurate risk stratification and prognostication. Traditional prognostic factors have been superseded by newer outcome predictors, including those defined by the molecular origin of the primary tumour.

METHODS

This review synthesized findings in the literature using the PubMed database of articles in the English language published between 1998 and 2017 on prognostic and predictive biomarkers in patients undergoing resection of CLMs.

RESULTS

Responses to preoperative chemotherapy define prognosis in patients undergoing CLM resection. There are differences by embryological origin too. Somatic mutations in the proto-oncogenes KRAS and NRAS are associated with positive surgical margins and tumour regrowth after ablation. Other mutations (such as BRAF) and co-occurring mutations in RAS/TP53 and APC/PIK3CA have emerged as important biomarkers that determine an individual patient's tumour biology and may be used to predict outcome after CLM resection.

CONCLUSION

Knowledge of somatic mutations can guide the use of preoperative therapy, extent of surgical margin and selection for ablation alone.

Genomic characterization of liver metastases from colorectal cancer patients

Metastatic dissemination is the most frequent cause of death of sporadic colorectal cancer (sCRC) patients. Genomic abnormalities which are potentially characteristic of such advanced stages of the disease are complex and so far, they have been poorly described and only partially understood. We evaluated the molecular heterogeneity of sCRC tumors based on simultaneous assessment of the overall GEP of both coding mRNA and non-coding RNA genes in primary sCRC tumor samples from 23 consecutive patients and their paired liver metastases. Liver metastases from the sCRC patients analyzed, systematically showed deregulated transcripts of those genes identified as also deregulated in their paired primary colorectal carcinomas. However, some transcripts were found to be specifically deregulated in liver metastases (vs. non-tumoral colorectal tissues) while expressed at normal levels in their primary tumors, reflecting either an increased genomic instability of metastatic cells or theiradaption to the liver microenvironment. Newly deregulated metastatic transcripts included overexpression of APOA1, HRG, UGT2B4, RBP4 and ADH4 mRNAS and the miR-3180-3p, miR-3197, miR-3178, miR-4793 and miR-4440 miRNAs, together with decreased expression of the IGKV1-39, IGKC, IGKV1-27, FABP4 and MYLK mRNAS and the miR-363, miR-1, miR-143, miR-27b and miR-28-5p miRNAs. Canonical pathways found to be specifically deregulated in liver metastatic samples included multiple genes related with intercellular adhesion and the metastatic processes (e.g., IGF1R, PIK3CA, PTEN and EGFR), endocytosis (e.g., the PDGFRA, SMAD2, ERBB3, PML and FGFR2), and the cell cycle (e.g., SMAD2, CCND2, E2F5 and MYC). Our results also highlighted the activation of genes associated with the TGFβ signaling pathway, -e.g. RHOA, SMAD2, SMAD4, SMAD5, SMAD6, BMPR1A, SMAD7 and MYC-, which thereby emerge as candidate genes to play an important role in CRC tumor metastasis.

Expression of SESN1, UHRF1BP1, and miR-377-3p as prognostic markers in mutated TP53 squamous cell carcinoma of the head and neck

The tumor suppressor gene TP53 is the most frequently mutated gene in human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC). It represents a known transcription factor that controls different microRNAs (miRNA) and target genes involved in the regulation of cellular stress, apoptosis and response to DNA damage. We used The Cancer Genome Atlas database to investigate the difference in transcriptome and proteome levels between mutated and wild-type TP53 HPV-negative HNSCC. Using different databases and an extensive literature review, we built the transcriptional and post-transcriptional network regulated by TP53. TP53 mutation was associated with poor overall survival in 203 HPV-negative patients compared to 40 patients with TP53 wild-type tumors. Using the enrichment analysis, we found that UHRF1BP1 and SESN1 mRNA were linked to prognosis in the TP53 mutated group. This is also the case for miR-377-3p, an important miRNA regulator of SESN1. Our study shows that SESN1 mRNA, UHRF1BP11 mRNA and miRNA-377-3p levels are prognostically relevant in HPV-negative HNSCC patients. This finding may help with patient stratification and the development of potential new therapeutic targets to treat patients with HNSCC.

Does anti-p53 antibody status predict for clinical outcomes in metastatic colorectal cancer patients treated with fluoropyrimidine, oxaliplatin, plus bevacizumab as first-line chemotherapy?

BACKGROUND

TP53 gene mutation is widely known as one of the determinants of impaired chemosensitivity. p53 is a tumor-suppressor protein in humans encoded by the TP53 gene. Some studies have shown that TP53 gene mutation and accumulation of the p53 protein are closely related with serum anti-p53 antibody positivity. This study aimed to evaluate the predictive significance of the serum p53 antibody status in metastatic colorectal cancer (mCRC) patients treated with fluoropyrimidine, oxaliplatin, plus bevacizumab as first-line chemotherapy.

METHODS

Ninety patients treated with fluoropyrimidine, oxaliplatin plus bevacizumab as first-line chemotherapy were enrolled, including 70 whose KRAS genotype was revealed at the beginning of treatment. Before chemotherapy initiation, the serum p53 antibody level was quantified by enzyme-linked immunosorbent assay using MESACUP® anti-p53 test kits. The cutoff value for positivity was 1.3 U/mL, as calculated previously. The KRAS genotype of the tumor samples was analyzed using the Luminex® assay.

RESULTS

Overall response rates of Response Evaluation Criteria in Solid Tumors criteria were 77.7 % (42/54) in anti-p53-negative patients and 69.4 % (25/36) in anti-p53-positive patients. The odds ratio was 1.07. Median overall survival was 36.1 months in the anti-p53-positive patients, and not available in the anti-p53-negative patients (hazard ratio, 0.81; 95 % confidence interval, 0.37-1.77; P = 0.61). The corresponding values for median progression-free survival were 13.3 months and 14.6 months (hazard ratio, 0.69; 95 % confidence interval, 0.41-1.17; P = 0.17), respectively.

CONCLUSIONS

Serum anti-p53 antibody positivity did not predict chemoresistance in mCRC treated with fluoropyrimidine, oxaliplatin, plus bevacizumab as first-line chemotherapy.

Distinct molecular features of different macroscopic subtypes of colorectal neoplasms

BACKGROUND

Colorectal adenoma develops into cancer with the accumulation of genetic and epigenetic changes. We studied the underlying molecular and clinicopathological features to better understand the heterogeneity of colorectal neoplasms (CRNs).

METHODS

We evaluated both genetic (mutations of KRAS, BRAF, TP53, and PIK3CA, and microsatellite instability [MSI]) and epigenetic (methylation status of nine genes or sequences, including the CpG island methylator phenotype [CIMP] markers) alterations in 158 CRNs including 56 polypoid neoplasms (PNs), 25 granular type laterally spreading tumors (LST-Gs), 48 non-granular type LSTs (LST-NGs), 19 depressed neoplasms (DNs) and 10 small flat-elevated neoplasms (S-FNs) on the basis of macroscopic appearance.

RESULTS

S-FNs showed few molecular changes except SFRP1 methylation. Significant differences in the frequency of KRAS mutations were observed among subtypes (68% for LST-Gs, 36% for PNs, 16% for DNs and 6% for LST-NGs) (P<0.001). By contrast, the frequency of TP53 mutation was higher in DNs than PNs or LST-Gs (32% vs. 5% or 0%, respectively) (P<0.007). We also observed significant differences in the frequency of CIMP between LST-Gs and LST-NGs or PNs (32% vs. 6% or 5%, respectively) (P<0.005). Moreover, the methylation level of LINE-1 was significantly lower in DNs or LST-Gs than in PNs (58.3% or 60.5% vs. 63.2%, P<0.05). PIK3CA mutations were detected only in LSTs. Finally, multivariate analyses showed that macroscopic morphologies were significantly associated with an increased risk of molecular changes (PN or LST-G for KRAS mutation, odds ratio [OR] 9.11; LST-NG or DN for TP53 mutation, OR 5.30; LST-G for PIK3CA mutation, OR 26.53; LST-G or DN for LINE-1 hypomethylation, OR 3.41).

CONCLUSION

We demonstrated that CRNs could be classified into five macroscopic subtypes according to clinicopathological and molecular differences, suggesting that different mechanisms are involved in the pathogenesis of colorectal tumorigenesis.

Can we improve the clinical risk score? The prognostic value of p53, Ki-67 and thymidylate synthase in patients undergoing radical resection of colorectal liver metastases

OBJECTIVES

The aim of this study was to assess whether biological markers can provide prognostic information additional to that supplied by the clinical risk score (CRS) in patients with colorectal liver metastases.

METHODS

A retrospective review of a prospectively maintained database was conducted. Patients selected for this study were treated between 1996 and 2011 with potentially curative liver surgery. Expressions of p53, Ki-67 and thymidylate synthase were assayed using immunohistochemical techniques on tissue microarrays.

RESULTS

A total of 98 (24%) of 406 patients met the inclusion criteria. The median follow-up was 103 months. Analysis revealed a correlation between p53 protein overexpression and high CRS (P = 0.058). Following multivariate analysis, only high CRS remained as an independent negative prognostic predictor of survival (P = 0.018), as well as an indicator of early recurrence of disease (P = 0.010). Of the biological markers investigated, only Ki-67 overexpression was identified as a positive predictor of survival on multivariate analysis (P = 0.038).

CONCLUSIONS

Ki-67 overexpression was a positive predictor of survival. Only high CRS remained an independent negative prognostic predictor.

SDF-1/CXCR4 axis promotes directional migration of colorectal cancer cells through upregulation of integrin αvβ6

Colorectal cancer (CRC) displays a predilection for metastasis to liver. Although stromal cell-derived factor-1 (SDF-1)/CXCR4 plays an important role in the liver metastasis, the molecular mechanism still remains obscure. We previously reported that integrin αvβ6 was implicated in the progression of CRC. However, no data are currently available on the cross talk between CXCR4 and αvβ6. In the present study, we first demonstrated the cross talk between CXCR4 and αvβ6 and their role in liver metastasis of CRC. We analyzed 159 human CRC samples and found that expression of CXCR4 and αvβ6 was significantly associated with liver metastasis, and interestingly expression of αvβ6 significantly correlated with expression of CXCR4. Both CXCR4 and αvβ6 were highly expressed in metastatic CRC cell lines HT-29 and WiDr, whereas both of them were exiguous in non-metastatic cell line Caco-2. Furthermore, inhibition of αvβ6 significantly decreased SDF-1α-induced cell migration in vitro. SDF-1/CXCR4 could upregulate αvβ6 expression through phosphorylation of ERK and activation of Ets-1 transcription factor. In conclusion, we demonstrate that SDF-1/CXCR4 induces directional migration and liver metastasis of CRC cells by upregulating αvβ6 through ERK/Ets-1 pathway. These data support combined inhibition of CXCR4 and αvβ6 to prevent development of liver metastasis of CRC.

Biological significance of promoter hypermethylation of p14/ARF gene: relationships to p53 mutational status in Tunisian population with colorectal carcinoma

One of the most important pathways which are frequently affected in colorectal cancer is p53/ (MDM2)/p14ARF pathway. We aim to determine the methylation pattern of p14/ARF in relation to mutation of p53. This correlation was studied to investigate whether their alterations could be considered as a predictor factor of prognosis in colorectal cancer and whether it can be useful in early-stage diagnosis. Statistical analyses show that p14/ARF hypermethylation was correlated with rectum location (p = 0.004), primary TNM stage (p = 0.016), and advanced Astler–Coller stage (p = 0.024). The RT-PCR that revel 31 % of patients did not express p14/ARF mRNA or at very low level. A high concordance between CpG hypermethylation and the low levels (p < 0.005) was shown. In addition, our analyses demonstrate that patients with mutation in the p53 gene have a lack of the protein expression (p < 0.005). This category with negative expression of p53 had a shorter survival rate (p < 0.005). On the one hand, MSP pattern of p14/ARF were correlated with a lack of p53 expression (p = 0.007). We found that p53/p14ARF pathway was frequently deregulated among our patients. In our study, we demonstrate that hypermethylation of p14/ARF occurs early during CRC tumorogenesis. However, we did not find correlation between p14/ARF and survival. These results suggest that p14/ARF methylation pattern may constitute a predictor factor of CRC in early stage but it could not be considered as a prognostic factor. On the other hand and because of the reversibility of the methylation mechanism, it may be appropriate to target the demethylation of p14/ARF to develop new drogues for CRC.

Characterization and Prognostic Value of Mutations in Exons 5 and 6 of the p53 Gene in Patients with Colorectal Cancers in Central Iran

BACKGROUND/AIMS

We aimed to investigate the relation-ships among various mutations of the p53 gene and their protein products, histological characteristics, and disease prognosis of primary colorectal cancer in Isfahan, central Iran.

METHODS

Sixty-one patients with colorectal adenocarcinoma were enrolled in the study. Mutations of the p53 gene were detected by single-stranded conformation polymorphism and DNA sequencing. The protein stability was evaluated by immunohistochemistry. Patients were followed up to 48 months.

RESULTS

Twenty-one point mutations in exons 5 and 6 were detected in the tumor specimens of 14 patients (23%). Of those, 81% and 9.5% were missense and nonsense mutations, respectively. There were also two novel mutations in the intronic region between exons 5 and 6. In 11 mutated specimens, protein stability and protein accumulation were identified. There was a relationship between the type of mutation and protein accumulation in exons 5 and 6 of the p53 gene. The presence of the mutation was associated with an advanced stage of cancer (trend, p<0.009). Patients with mutated p53 genes had significantly lower survival rates than those with wild type p53 genes (p<0.01).

CONCLUSIONS

Mutations in exons 5 and 6 of the p53 gene are common genetic alterations in colorectal adenocarcinoma in central Iran and are associated with a poor prognosis of the disease.

Decrease of survivin, p53 and Bcl-2 expression in chemorefractory colorectal liver metastases may be predictive of radiosensivity radiosensivity after radioembolization with yttrium-90 resin microspheres

In a prospective multicenter phase II trial of radioembolization with yttrium-90 (⁹⁰Y-RE) in chemorefractory liver-dominant metastatic colorectal cancer (mCRC), we showed that median survival was 12.6 months (95% CI 7.0–18.3) with 48% of 50 patients achieving disease control. In this extension retrospective study, we analyzed whether a panel of biomarkers, known to be associated to an adverse clinical outcome, underwent variations in CRC liver metastases pre and post ⁹⁰Y-RE.

Of the 50 patients included in the study, 29 pre-⁹⁰Y-RE therapy and 15 post-⁹⁰Y-RE had liver biopsy specimens available. In these series we investigated survivin, p53, Bcl-2 and Ki-67 expression pre- and post-⁹⁰Y-RE by immuhistochemistry (IHC). Our findings evidenced a decrease of survivin (77% vs 33%), p53 (93% vs 73%), Bcl-2 (37% vs 26%) expression as well as of Ki-67 proliferation index (62.5% vs 40%) on liver biopsies collected post-⁹⁰Y-RE as compared to pre-⁹⁰Y-RE. In the subset of 13 matched liver metastases we further confirmed the reduction of survivin (92.3% vs 53.8%; p = 0.06), p53 (100% vs 69.2%; p = 0.05) and Bcl-2 (69.2% vs 53.8%; p = 0.05) expression post-⁹⁰Y-RE. This biomarker modulation was accompanied by morphological changes as steatohepatitis, hepatocyte necrosis, collagen deposition, proliferating and/or bile duct ectasia, focal sinusoidal dilatation and fibrosis.

Although our analysis was conducted in a very limited number cases, these changes appear strictly related to the response to ⁹⁰Y-RE therapy and may deserve further investigation on a larger series of patients.

Mutations and polymorphisms in TP53 gene--an overview on the role in colorectal cancer

A functionally normal TP53 is essential to protect organisms from developing cancer. Somatic mutations in the gene represent one of the highest recurring perturbations in human tumours, including colorectal cancer (CRC). However, the variegated phenotype of wide spectrum of somatic mutations in TP53 and the complexity of the disease prevent a straight interpretation of the mutational analysis in tumours. In addition to the presence of somatic mutations, polymorphic features of the gene may also contribute to alteration of the normal TP53 functioning and variants, mainly in the form of single nucleotide polymorphisms, can be expected to impact susceptibility to sporadic CRC. In the present study, we reviewed the potential role of alterations in the TP53 gene, both somatic mutations and inherited sequence variations, in predisposition to CRC and in the prognosis and response to therapy. The available data from association studies have mostly shown contradictory outcomes. The majority of the studies were based on limited sample sizes and focussed on a limited number of polymorphisms, with main being the rs1042522 (Arg72Pro). Thus far, there is no possible generalisation of the role of TP53 as also a predictor of therapeutic response and prognosis. The effects of TP53, and its abnormalities, on the response of tumours to cytotoxic drugs, radiation and chemoradiation are complex. However, from studies it is emerging that the inherited genetics of TP53 pathway components could be utilised to further define patient populations in their abilities to induce p53 activity in response to either DNA damaging or p53-targeted therapies.

Association between colorectal cancer and tumor suppressor genes: recent research progress

Colorectal cancer is a common high-risk gastrointestinal cancer, and approximately 1.2 million new cases are diagnosed each year worldwide. In recent years, due to the improvement of people's living standards and changes in dietary habits and structure, the incidence and mortality rate of colorectal cancer increase rapidly in China. Moreover, patients have a significantly earlier age of onset. At present, the median age of colorectal cancer onset in China is 58 years old, 12 to 18 years earlier than other countries in Europe and America. The development of colorectal cancer is a complex multi-stage process involving multiple genetic alterations. Many studies have shown that colorectal carcinogenesis involves activation of oncogenes and inactivation of tumor suppressor genes. Tumor suppressor genes associated with colorectal carcinogenesis include p53, APC, DCC, and MMR, and proto-oncogenes include K-ras and c-myc. In this paper, we discuss the association between tumor suppressor genes and colorectal carcinogenesis.

Prognostic significance and gene expression profiles of p53 mutations in microsatellite-stable stage III colorectal adenocarcinomas

Although the prognostic value of p53 abnormalities in Stage III microsatellite stable (MSS) colorectal cancers (CRCs) is known, the gene expression profiles specific to the p53 status in the MSS background are not known. Therefore, the current investigation has focused on identification and validation of the gene expression profiles associated with p53 mutant phenotypes in MSS Stage III CRCs. Genomic DNA extracted from 135 formalin-fixed paraffin-embedded tissues, was analyzed for microsatellite instability (MSI) and p53 mutations. Further, mRNA samples extracted from five p53-mutant and five p53-wild-type MSS-CRC snap-frozen tissues were profiled for differential gene expression by Affymetrix Human Genome U133 Plus 2.0 arrays. Differentially expressed genes were further validated by the high-throughput quantitative nuclease protection assay (qNPA), and confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and by immunohistochemistry (IHC). Survival rates were estimated by Kaplan-Meier and Cox regression analyses. A higher incidence of p53 mutations was found in MSS (58%) than in MSI (30%) phenotypes. Both univariate (log-rank, P = 0.025) and multivariate (hazard ratio, 2.52; 95% confidence interval, 1.25-5.08) analyses have demonstrated that patients with MSS-p53 mutant phenotypes had poor CRC-specific survival when compared to MSS-p53 wild-type phenotypes. Gene expression analyses identified 84 differentially expressed genes. Of 49 down-regulated genes, LPAR6, PDLIM3, and PLAT, and, of 35 up-regulated genes, TRIM29, FUT3, IQGAP3, and SLC6A8 were confirmed by qNPA, qRT-PCR, and IHC platforms. p53 mutations are associated with poor survival of patients with Stage III MSS CRCs and p53-mutant and wild-type phenotypes have distinct gene expression profiles that might be helpful in identifying aggressive subsets.

Predictors of long-term survival in patients with colorectal liver metastases: a single center study and review of the literature

PURPOSE

Prognosis after resection of liver metastases of colorectal cancer is influenced by a variety of clinical factors. For more than 20 years, efforts have been made to restructure and simplify prognostic parameters into clinical scores. We evaluated the influence of various clinical and pathological factors on survival and recurrence and developed a simple model for risk stratification.

METHODS

We have analyzed a total of 13 prognostic factors in 382 consecutive and prospectively enrolled R0-resected patients and applied our data set to ten published prognostic scoring systems. Prognostic factors that influenced disease-specific and disease-free survival were included into a model clinical risk score.

RESULTS

The 5- and 10-year observed survival rates were 43% and 28%, respectively, for all 382 patients. The disease-specific 5- and 10-year survival rates were 49% and 37%, respectively; the 5- and 10-year recurrence rates were 68% and 70%, respectively. For patients with synchronous liver metastases, survival was not affected by the timing of liver resection. The prognosis after treatment of any recurrence was best after the accomplishment of a repeated R0 situation, independent of the location of the recurrence. In the multivariate analysis, the disease-specific survival and recurrence rates were statistically significantly influenced by more than three lymph node metastases of the primary tumor, more than two lesions within the liver, and the presence of extrahepatic tumor.

CONCLUSIONS

From these data, we have developed a simple score for the risk stratification which may be useful for future studies on interdisciplinary management of colorectal liver metastases.

High expression of testes-specific protease 50 is associated with poor prognosis in colorectal carcinoma

Background

Testes-specific protease 50 (TSP50) is normally expressed in testes and abnormally expressed in breast cancer, but whether TSP50 is expressed in colorectal carcinoma (CRC) and its clinical significance is unclear. We aimed to detect TSP50 expression in CRC, correlate it with clinicopathological factors, and assess its potential diagnostic and prognostic value.

Methodology/Principal Findings

TSP50 mRNAs and proteins were detected in 7 CRC cell lines and 8 CRC specimens via RT-PCR and Western blot analysis. Immunohistochemical analysis of TSP50, p53 and carcinoembryonic antigen (CEA) with tissue microarrays composed of 95 CRCs, 20 colorectal adenomas and 20 normal colorectal tissues were carried out and correlated with clinicopathological characteristics and disease-specific survival for CRC patients. There was no significant correlation between the expression levels of TSP50 and p53 (P = 0.751) or CEA (P = 0.663). Abundant expression of TSP50 protein was found in CRCs (68.4%) while it was poorly expressed in colorectal adenomas and normal tissues (P<0.0001). Thus, CRCs can be distinguished from them with high specificity (92.5%) and positive predictive value (PPV, 95.6%). The survival of CRC patients with high TSP50 expression was significantly shorter than that of the patients with low TSP50 expression (P = 0.010), specifically in patients who had early-stage tumors (stage I and II; P = 0.004). Multivariate Cox regression analysis indicated that high TSP50 expression was a statistically significant independent risk factor (hazard ratio  = 2.205, 95% CI = 1.214–4.004, P = 0.009).

Conclusion

Our data demonstrate that TSP50 is a potential effective indicator of poor survival for CRC patients, especially for those with early-stage tumors.

When mutants gain new powers: news from the mutant p53 field

Ample data indicate that mutant p53 proteins not only lose their tumour suppressive functions, but also gain new abilities that promote tumorigenesis. Moreover, recent studies have modified our view of mutant p53 proteins, portraying them not as inert mutants, but rather as regulated proteins that influence the cancer cell transcriptome and phenotype. This influence is clinically manifested as association of TP53 mutations with poor prognosis and drug resistance in a growing array of malignancies. Here, we review recent studies on mutant p53 regulation, gain-of-function mechanisms, transcriptional effects and prognostic association, with a focus on the clinical implications of these findings.

Clinical significance of microvessel count in patients with metastatic liver cancer originating from colorectal carcinoma

BACKGROUND

Microvessel count (MVC) has been correlated with patient prognosis in hepatocellular carcinoma. We investigated whether MVC assessed by staining with CD34 antibody was associated with disease-free and overall survival in patients with metastatic liver cancer (MLC).

METHODS

We examined relationships between MVC and clinicopathologic factors or postoperative outcomes in 139 MLC patients who underwent hepatectomy between 1990 and 2006. CD34 expression was analyzed by the immunohistochemical method.

RESULTS

MVC was associated with fibrous pseudocapsular formation on histological examination. By means of the modern Japanese classification of liver metastasis, poorer survival was associated with higher score, poorly differentiated adenocarcinoma, higher preoperative carcinoembryonic antigen (CEA) level, fibrous pseudocapsular formation, and smaller surgical margin. Shorter disease-free survival was associated with higher score when the Japanese classification of liver metastasis was used, multiple or bilobar tumor, regional lymph node metastasis in primary colon carcinoma, preoperative CEA level, fibrous pseudocapsular formation, and smaller surgical margin (<5 mm). Higher MVC (>or=406/mm(2)) was associated with decreased disease-free and overall survival by univariate analysis (P = .034 and P = .021, respectively), and higher MVC represented an independently poor prognostic factor in overall survival by Cox multivariate analysis (risk ratio, 2.71; P = .023) in addition to histological differentiation.

CONCLUSIONS

Tumor MVC seems to be a useful prognostic marker of MLC patient survival.

Poorer outcome in stromal HIF-2 alpha- and CA9-positive colorectal adenocarcinomas is associated with wild-type TP53 but not with BNIP3 promoter hypermethylation or apoptosis

Stromal expression of hypoxia inducible factor 2α (HIF-2α) and carbonic anhydrase 9 (CA9) are associated with a poorer prognosis in colorectal cancer (CRC). Tumour cell death, regulated by a hypoxic stromal microenvironment, could be of importance in this respect. Therefore, we correlated apoptosis, TP53 mutational status and BNIP3 promoter hypermethylation of CRC cells with HIF-2α- and CA9-related poor outcome. In a series of 195 CRCs, TP53 mutations in exons 5–8 were analysed by direct sequencing, and promoter hypermethylation of BNIP3 was determined by methylation-specific PCR. Expressions of HIF-2α, CA9, p53, BNIP3 and M30 were analysed immunohistochemically. Poorer survival of HIF-2α and CA9 stromal-positive CRCs was associated with wild-type TP53 (P=0.001 and P=0.0391), but not with BNIP3 methylation. Furthermore, apoptotic levels were independent of the TP53 status, but lower in unmethylated BNIP3 CRCs (P=0.004). It appears that wild-type TP53 in CRC cells favours the progression of tumours expressing markers for hypoxia in their stroma, rather than in the epithelial compartment. Preserved BNIP3 function in CRC cells lowers apoptosis, and may thus be involved in alternative cell death pathways, such as autophagic cell death. However, BNIP3 silencing in tumour cells does not impact on hypoxia-driven poorer prognosis.

These results suggest that the biology of CRC cells can be modified by alterations in the tumour microenvironment under conditions of tumour hypoxia.