Current status of adjuvant chemotherapy for colorectal cancer. Can molecular markers play a role in predicting prognosis?

Prognostic factors for survival after curative resection of Dukes' B colonic cancer

AIM

Data on the prognostic factors for survival in patients with locally advanced, node-negative colon cancer are limited. This study aimed to determine which factors might predict survival in patients with Dukes' B (T3 or T4, N0) colon cancer.

METHOD

One hundred and eighty (93 male; median age 75 [range, 38-96] years) consecutive patients who had resection of a primary Dukes' B (on final histopathological analysis) colonic cancer between 1998 and 2003 were studied. No patient received neoadjuvant chemotherapy. Multivariate Cox regression modelling was used to assess the prognostic value of variables. Median follow up was 85 (60-125) months.

RESULTS

Thirteen (7%) patients had a perforation at presentation. The median distance from tumour to the nearest longitudinal resection margin was 6 (0.3-27) cm. One hundred and twenty-four (69%) patients had a lymph node yield of 12 or more nodes. Actual 5-year survival was 59%. On multivariate regression analysis, tumour perforation (perforation vs no perforation, 5-year survival, 23%vs 61%; hazard ratio (HR), 3.7; 95% confidence interval (CI), 1.6-8.4; P = 0.002), tumour-to-margin distance (< 5 cm vs ≥ 5 cm, 48%vs 65%; HR, 1.7; 95% CI, 1.1-2.7; P = 0.039) and older age (≥ 75 years vs < 75 years, 45%vs 72%; HR, 3; 95% CI, 1.8-5; P < 0.001) were independent significant variables.

CONCLUSION

A lymph node yield of 12 or more nodes is not a significant prognostic factor for survival after resection of Dukes' B colonic cancer. Patients with tumour perforation or limited resection have worse prognosis.

A review of the most promising biomarkers in colorectal cancer: one step closer to targeted therapy

Rapidly growing insights into the molecular biology of colorectal cancer (CRC) and recent developments in gene sequencing and molecular diagnostics have led to high expectations for the identification of molecular markers to be used in optimized and tailored treatment regimens. However, many of the published data on molecular biomarkers are contradictory in their findings and the current reality is that no molecular marker, other than the KRAS gene in the case of epidermal growth factor receptor (EGFR)- targeted therapy for metastatic disease, has made it into clinical practice. Many markers investigated suffer from technical shortcomings, resulting from lack of quantitative techniques to capture the impact of the molecular alteration. This understanding has recently led to the more comprehensive approaches of global gene expression profiling or genome-wide analysis to determine prognostic and predictive signatures in tumors. In this review, an update of the most recent data on promising biological prognostic and/or predictive markers, including microsatellite instability, epidermal growth factor receptor, KRAS, BRAF, CpG island methylator phenotype, cytotoxic T lymphocytes, forkhead box P3-positive T cells, receptor for hyaluronic acid-mediated motility, phosphatase and tensin homolog, and T-cell originated protein kinase, in patients with CRC is provided.

Increased TGF-beta 1 protein expression in patients with advanced colorectal cancer

INTRODUCTION

There is evidence that TGF-beta 1 plays a role as a tumor suppressor in early disease and has pro-oncogenic effects in advanced tumor stage. The aim of the study was to correlate TGF-beta 1 in plasma and tissue to clinical and pathological parameters in patients with various stages of disease progression.

METHODS

One hundred sixty-nine patients who underwent surgery for a colorectal carcinoma were prospectively included. Blood samples, tumor free mucosa and tumor biopsies were assayed.

RESULTS

TGF-beta 1 protein expression in tumors increased with increasing T-stage regardless of whether patients with metastatic disease were included or not (P = 0.0006). Patients with metastatic disease showed elevated TGF-beta 1 protein expression in both tumor tissue (P = 0.004) and plasma (P = 0.001) compared to those without metastatic disease. TGF-beta 1 protein expression was higher in the colon compared with the rectum in both tumor tissue and tumor-free bowel (P = 0.03), regardless of whether patients with metastatic disease were included or not. This difference was mainly attributable to a higher TGF-beta 1 protein expression in non-metastatic patients with lymph node positivity (P = 0.005).

CONCLUSIONS

Higher TGF-beta 1 protein expression is associated with increasing T-stage and metastatic disease, indicating that TGF-beta 1 is of importance in tumor progression. The localization of the tumor seems to influence the TGF-beta 1 protein expression in patients with tumor cell-positive lymph nodes.

Matrix metalloproteinase-9 activity is associated with poor prognosis in T3-T4 node-negative colorectal cancer

Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a novel membrane-anchored matrix metalloproteinase (MMP) inhibitor. RECK, MMP-2, and MMP-9 are believed to play crucial roles in tumor progression. This study was designed to examine the prognostic value of RECK, MMP-2, and MMP-9 in conjunction with other clinicopathologic factors in patients of T3-T4 node-negative colorectal cancer. RECK and MMP expression was observed using immunohistochemical analysis of the primary tumor from 89 patients with curatively resected T3-4 N0 colorectal cancer retrospectively. High RECK expression was observed in 51 cases, whereas expression was low in the other 38 cases. MMP-2 and MMP-9 expression was positive in cancer cells in 24 and 33 cases, respectively. RECK and MMP-2 expression was not significantly associated with any clinicopathologic factors. However, expression of MMP-9 was correlated with tumor location. A statistically significant inverse correlation was found between RECK and MMP-2 expression, and a statistically significant correlation was found between MMP-2 and MMP-9 expression. However, no association between RECK and MMP-9 expression was observed. Univariate analysis demonstrated that rectal tumor location, preoperative carcinoembryonic antigen more than 5 ng/mL, positive lymphatic invasion, less than 12 dissected lymph nodes, and positive MMP-9 expression were poor prognostic factors of disease-free survival. A multivariate analysis confirmed that enhanced MMP-9 expression was an independent and significant factor for prediction of a poor prognosis. In addition, positive lymphatic invasion and less than 12 dissected lymph nodes were significant negative prognostic factors. In conclusion, MMP-9 status represents a novel prognostic factor in evaluation of T3-T4 node-negative colorectal cancer.

Immunoprofiles of 11 biomarkers using tissue microarrays identify prognostic subgroups in colorectal cancer

BACKGROUND AND AIMS

Genomewide expression profiling has identified a number of genes expressed at higher levels in colorectal cancer (CRC) than in normal tissues. Our objectives in this study were: 1) to test whether genes were also distinct on the protein level; 2) to evaluate these biomarkers in a series of well-characterized CRCs; and 3) to apply hierarchical cluster analysis to the immunohistochemical data.

METHODS

Tissue microarrays (TMAs) comprising 351 CRC specimens from 270 patients were constructed to evaluate the genes Adam10, Cyclin D1, Annexin II, NFKB, Casein kinase 2 beta (CK2B), YB-1, P32, Rad51, c-fos, IGFBP4, and Connexin26 (Cx26). In total, 3,797 samples were analyzed.

RESULTS

Unsupervised hierarchical clustering discovered subgroups of CRC that differed by tumor stage and survival. Kaplan-Meier analysis showed that reduced Cx26 expression was significantly associated with shorter patient survival and higher tumor grade (G1/G2 vs G3, P = .02), and Adam10 expression with a higher tumor stage (pT1/2 vs pT3/4, P = .04).

CONCLUSIONS

Our study highlights the potential of TMAs for a higher-dimensional analysis by evaluating serial sections of the same tissue core (three-dimensional TMA analysis). In addition, it endorses the use of immunohistochemistry supplemented by hierarchical clustering for the identification of tumor subgroups with diagnostic and prognostic signatures.

A systematic review and meta-analysis of the relationship between chromosome 18q genotype, DCC status and colorectal cancer prognosis

Results from studies investigating the relationship between colorectal cancer survival and chromosome 18q allelic imbalance (AI)/loss of DCC expression (LOE) have been inconsistent. We have reviewed and pooled published studies to estimate the prognostic significance of chromosome 18q status more precisely. Data from 27 studies were eligible. Survival data were pooled using standard meta-analysis techniques. Considerable variation between assessment method, marker choice, and threshold for assigning AI/LOE was observed. Pooling data from a 2189 cases from 17 studies showed significantly worse overall survival in patients with AI/LOE (HR = 2.00, 95%CI: 1.49-2.69), maintained both in the adjuvant setting (HR = 1.69, 95%CI:1.13-2.54), and also by method (HR = 1.67, 95%CI: 1.19-2.36, genotyping microsatellites; HR = 3.00, 95%CI: 1.98-4.56, immunohistochemistry). There was however evidence of heterogeneity and publication bias. Cancers with chromosome 18q loss appear to have a poorer prognosis. Prospective studies using consistent methodology are needed to precisely quantify its effect and role in patients with stage II-III disease.

GNAS1 T393C polymorphism and survival in patients with sporadic colorectal cancer

PURPOSE

Signaling via the G protein Galpha s pathway is linked to proapoptotic processes in cancer cell lines. We have recently shown an association between the GNAS1 T393C polymorphism and disease progression in patients with bladder cancer with homozygous TT genotypes displaying increased transcription of Galpha s and a more favorable clinical course compared with C-allele carriers.

EXPERIMENTAL DESIGN

In the present study, 151 patients with sporadic colorectal cancer were retrospectively genotyped to examine a potential association between T393C genotypes and survival. Moreover, two other single-nucleotide polymorphisms in common haplotype blocks within the gene GNAS1 and their interaction with the T393C polymorphism were investigated.

RESULTS

The allele frequency in the patients group was not significantly different from that of healthy blood donors. Kaplan-Meier curves for overall survival (mean follow-up, 43 months) showed that in International Union Against Cancer (UICC) stages I to II, the 5-year survival rate was significantly higher in TT genotypes (87.8%) compared with TC (71.0%) and CC genotypes (50.0%; P = 0.009), whereas no genotype effect could be observed for UICC stages III to IV. In multivariate Cox proportional analysis the T393C polymorphism was an independent prognostic factor for survival. Homozygous CC patients were at highest risk for death (hazard ratio, 12.1; P = 0.006) compared with TT genotypes. Heterozygous patients had an intermediate risk compatible with a gene-dose effect. The two haplotype blocks investigated were not associated with clinical outcome.

CONCLUSIONS

The results support the role of the T393C polymorphism as a marker for survival in patients with colorectal cancer stages I to II and in the identification of patients who may benefit from adjuvant chemotherapy.

Evolution of intratumoral genetic heterogeneity during colorectal cancer progression

Evolution of intratumoral genetic heterogeneity during colorectal tumor progression has not been investigated so far. Multiple sample areas in colorectal adenocarcinoma at early and advanced stages and in metastases were studied for the well-known genetic alterations: K-ras and p53 point mutations and loss of heterozygosity (LOH) on chromosomes 5q and 18q. In primary colorectal cancers (CRCs), intratumoral genetic heterogeneity was more often observed in early than in advanced stages, at 90 and 67%, respectively. All but one of the advanced CRCs were composed of one predominant clone and other minor clones, whereas no predominant clone has been identified in half of the early cancers. At the early stage, the last events that were produced, the p53 mutation and LOH of 18q, were also the most heterogeneous. At the advanced stage, the LOH of 5q and 18q were the most frequent heterogeneous events (67 and 58%, respectively). The intratumoral heterogeneity for mutations was significantly reduced, from the early to the advanced stages (from 60 to 20% for K-ras and from 70 to 20% for p53). On the other hand, a quasi absence of intratumoral genetic heterogeneity was observed for K-ras and p53 in distant metastasis. In conclusion, colorectal adenocarcinomas are characterized by marked intratumoral genetic heterogeneity. A reduction of the intratumoral genetic heterogeneity for point mutations and a relative stability of the heterogeneity for allelic losses indicate that, during the progression of CRC, clonal selection and chromosome instability continue, while an increase cannot be proven.

Colon cancer: survival after curative surgery

Several new aspects have evolved during the past years concerning factors that influence survival in surgically and medically treated colon cancer patients that are relevant to the treating team for the treatment strategy and patient's choice. The 5-year-survival rates dependent on UICC stages/substages (I: 68%-100%, II: 58%-90%, III: 33%-76%, IV: <5%-9%) show remarkable variations between published reports, surgical hospital units, individual surgeons, and continents (USA vs Europe). Those variations may be due to surgical techniques, training status, hospital and individual case volume, and, also, referral patterns and statistical evaluation methods. Survival times and cure rates are significantly improved by adjuvant chemotherapy in UICC III and in substages of UICC II (e.g. UICC II B) by 5%-12%, when compared with surgical controls. In three recently published trials standard adjuvant chemotherapy was further improved by increased survival rates, e.g. from 59% to 71% in stage III and IIB patients. Molecular and genetic factors, such as thymidylate synthase (TS), microsatellite instability (MSI) or loss of chromosome 18q/"DCC" might have an independent impact on prognosis in the spontaneous course, and TS could help to better select patients for adjuvant chemotherapy.

Systematic review of genetic influences on the prognosis of colorectal cancer

Background

In terms of genetics, colorectal cancer is one of the best understood of all malignant diseases. Genetic influences on prognosis may have far-reaching implications, especially for the design of surgical and chemoradiotherapeutic regimens. However, their significance in determining prognosis remains unclear. This study aimed to review the literature on the specific role of key genes in determining the survival of patients with colorectal cancer.

Methods

A Medline search was carried out to identify all original scientific papers relating colorectal cancer genetics to patient survival, up to December 2002. Cochrane and Embase databases were also searched. Identified articles were retrieved and searched carefully for additional information. This review includes K-ras, p53, DCC, NM23 and DNA mismatch repair genes.

Results and conclusion

Conflicting evidence exists as to the prognostic significance of genes commonly implicated in the pathogenesis of colorectal carcinoma. Possible causes for such discrepancy include differences in study methods and laboratory techniques, variable duration of follow-up, statistical differences in study power, and heterogeneity in study populations. Future studies should adopt standardized protocols to define clinically relevant genetic observations.

Association between recurrence of sporadic colorectal cancer, high level of microsatellite instability, and loss of heterozygosity at chromosome 18q

PURPOSE

Microsatellite instability and loss of heterozygosity of chromosomes 18q, 8p, and 4p are genetic alterations commonly found in colorectal cancer. We investigated whether these genetic markers allow for the stratification of patients with Stage II to III colorectal cancer into groups with different recurrence risks, and with different prognoses.

METHODS

Tumors of 113 patients were evaluated for loss of heterozygosity of chromosomes 18q, 8p, and 4p and for microsatellite instability by use of six microsatellite markers. Genetic alterations involving each of these genetic markers were examined for association with disease recurrences and survival.

RESULTS

Loss of heterozygosity of chromosomes 18q, informative in 96 percent of cases, in Stage III tumors was associated with higher risk of overall recurrence ( P< 0.001), local recurrence ( P< 0.001), distant metastases ( P< 0.001), decreased overall survival ( P= 0.002), and disease-free survival ( P< 0.001). The recurrence rates and survival rates among patients with Stage II colorectal cancer were independent of loss of heterozygosity of chromosome 18q. Stage III and loss of heterozygosity of chromosome 8p also were associated with a higher risk of recurrences when these factors were considered individually. In multivariate analysis, only loss of heterozygosity of chromosome 18q was independently associated with risk of recurrences ( P < 0.001) and with disease-free survival ( P= 0.001). No correlation was observed between microsatellite instability and recurrence rates. However, microsatellite instability was associated with improved overall survival ( P= 0.04) and with a longer disease-free interval ( P= 0.002). Only in five cases (16.7 percent) was it possible to perform resection of recurrences; two of these patients had microsatellite instability tumor. In no cases was it possible to resect recurrence of tumors with loss of heterozygosity of chromosome 18q.

CONCLUSIONS

Loss of heterozygosity of chromosome 18q is an informative genetic marker, which in resected Stage III colorectal cancer can be used to predict recurrences and survival. Microsatellite instability identified cases that, even in the case of recurrence, have a more favorable prognosis.

Genetic imbalances with impact on survival in colorectal cancer patients

AIMS

To investigate the prognostic significance of chromosomal alterations in colorectal cancer patients. Histopathological tumour classification is still considered to be the gold standard for the characterization of solid tumours. However, it is well known that such established parameters do not satisfactorily predict the clinical outcome in individual cases. Markers that reliably predict survival are needed. These markers should guide the clinical treatment of neoplastic disease.

METHODS AND RESULTS

Chromosomal imbalances in 61 colorectal carcinoma specimens in 37 patients determined by comparative genomic hybridization were correlated with patient survival using custom-made computer software which enabled the assessment of individual chromosomal loci. Kaplan-Meier analysis revealed that over-representations of 2p14-15, 6q23-6q24, 15q22-15q23, 22q11.2 and deletions of 1p36.1-36.2, 4q31.3, 4q35, 8q12-q21, 8p11.2 and 9p22 were significantly associated with shorter disease-specific survival, whereas over-expression of 20q13.3 and deletion of 18q11.2 were significantly associated with longer disease-specific survival in this collection of colorectal cancers. Multivariate Cox proportional hazards regression models consistently identified gains of 2p14-15, 15q22-23, 22q11.2 and losses of 1p36.1-36.2 and 4q35 as independent markers of shorter patient survival carrying greater significance than the classical clinicopathological parameters of nodal status and tumour grade.

CONCLUSIONS

These five markers allow a molecular categorization of patients into high and low clinical risk groups. Thus, the genomic data have refined the histopathological classification highlighting the necessity for a supplementary genetically based stratification of colorectal cancer.

Genetic tumor markers with prognostic impact in Dukes' stages B and C colorectal cancer patients

PURPOSE

To examine several genetic changes in primary colorectal carcinomas (CRCs) from patients with 10 years of follow-up and associate the findings with clinicopathologic variables.

MATERIAL AND METHODS

DNA from 220 CRCs were analyzed for allelic imbalances at 12 loci on chromosome arms 1p, 14q, 17p, 18q, and 20q, and the microsatellite instability (MSI) status was determined. The clinical significance of the tumor protein 53 (TP53) mutations was re-evaluated.

RESULTS

Patients with tumors containing 17p or 18q deletions had shorter survival than those without these alterations (P =.021, P =.008, respectively). This was also significant for the Dukes' B group (P =.025, P =.010, respectively). Furthermore, patients with tumors showing losses of both chromosome arms revealed an even poorer disease outcome than those with either 17p or 18q loss. Patients with low increase in 20q copy number in their tumors had longer survival compared with those without changes (P =.009) or those with a high increase of copy number (P =.037). This was also evident for the Dukes' C group (P =.018, P =.030, respectively). MSI was seemingly a beneficial marker for survival (P =.071). A significant association between mutations affecting the L3 zinc-binding domain of TP53 and survival was confirmed in this cohort after 10 years of follow-up, and also was found to apply for patients in the Dukes' B group. Several associations were found among genetic and pathologic data.

CONCLUSION

The present study indicates that 17p, 18q, and 20q genotypes, and TP53 mutation status add information in the subclassification of Dukes' B and C patients and may have impact on the choice of treatment.

Numerical abnormalities of chromosomes 17 and 18 in sporadic colorectal cancer: Incidence and correlation with clinical and biological findings and the prognosis of the disease

BACKGROUND

In recent years important information has accumulated on the genetic alterations present in colorectal tumors. However, thus far few studies have analyzed the impact of numerical abnormalities of chromosomes 17 and 18, which carry the p53 and DCC plus SHAD4/DPC4 genes involved in colorectal cancer, on the clinical and biological behaviors of the disease.

METHODS

With the use of interphase fluorescence in situ hybridization (FISH), we analyzed the incidence of numerical abnormalities of chromosomes 17 and 18 in a series of malignant colorectal tumors and explored its potential association with clinicobiological behavior and the prognosis of the disease. For this purpose, 94 consecutive patients newly diagnosed with colorectal cancer were analyzed. In all cases, FISH analyses of the number of copies and nuclei of chromosomes 17 and 18 were performed in interphase nuclei with the use of double stainings. For all patients, information on age, sex, tumor size, Dukes' stage, tumor localization, DNA ploidy status, and the proportion of S-phase tumor cells was recorded. Median follow-up was 38 months.

RESULTS

Numerical abnormalities of chromosomes 17 and 18 were present in most patients with colorectal cancer (57% and 52%, respectively). Gains of chromosome 17 and monosomy 18 were found in 51% and 29% of cases, respectively, and they were the most frequent individual abnormalities for each chromosome. The simultaneous analysis of the number of copies of both chromosomes in the same cell showed that, in most cases displaying numerical abnormalities for these chromosomes, two or more different tumor cell clones were present. From a clinical point of view, numerical abnormalities of chromosome 17, especially monosomy 17, were associated with a significantly higher incidence of rectal tumors (P = 0.001) and Dukes' stage D (P = 0.02) and a lower median of disease-free survival among patients who underwent curative surgery (P = 0.05), as compared with diploid cases. In addition, cases with an altered number of copies of chromosome 17 showed a higher incidence of DNA aneuploidy (P = 0.0001) and a greater proportion of S-phase cells (P = 0.001) by flow cytometry. In contrast, no clear association was found between the presence of numerical abnormalities of chromosome 18 and clinicobiological disease characteristics, except for a higher incidence of DNA aneuploidy by flow cytometry (P = 0.001) and a lower median of disease-free survival (P = 0.06). Multivariate analysis showed that numerical abnormalities of chromosome 17, but not of chromosome 18, are an independent prognostic factor for predicting disease-free survival in patients with colorectal cancer.

CONCLUSIONS

Numerical abnormalities of chromosomes 17 and 18 were relatively common findings in patients with colorectal cancer, with chromosome 17 being associated with a higher incidence of tumors localized to the rectum and a worse clinical outcome. Cytometry Part B (Clin. Cytometry) 51B:14-20, 2003.

Overexpression of c-erbB-2 protein correlates with chromosomal gain at the c-erbB-2 locus and patient survival in advanced colorectal carcinomas

Overexpression of the c-erbB-2 protein (also called HER-2/neu) is observed in a variety of malignancies including colorectal cancer (CRC). In this study we aimed to evaluate the rate of c-erbB-2 overexpression in our tumor collection and to clarify its correlation with the chromosomal status at the c-erbB-2 locus in CRC. Additionally we correlated the c-erbB-2 overexpression and the chromosomal gain of 17q with patient survival. Seventy-four specimens were analyzed immunohistochemically using a polyclonal c-erbB-2 antibody (DAKO) and the staining was scored according to the Clinical Trial Assay recommendations (0-3+). Of these, 45 cases were analyzed by comparative genomic hybridization (CGH) and immunohistochemistry (IHC). Overexpression was observed in 51% of the cases (score > or = 2). Chromosomal gains at the c-erbB-2 locus were clearly correlated with overexpression of the gene (P = 0.0009). Furthermore Kaplan-Meier analysis showed that overexpression of c-erbB-2 was significantly associated with poor survival and thus could serve as a prognostic marker. We conclude that c-erbB-2 is related with tumor progression in CRC which can be observed on protein level and reflects chromosomal gain at the locus at 17q.

Chromosome 6p21.2, 18q21.2 and human papilloma virus (HPV) DNA can predict prognosis of cervical cancer after radiotherapy

Loss of heterozygosity (LOH) is one of the most important mechanisms for inactivation of tumor-suppressor genes. Studies of LOH in patients with cervical carcinoma have reported a high frequency of LOH on 3p21.3, 6p21.2, 17p13.1, and 18q21.2. Our study explored whether p53 status, human papilloma virus (HPV), and LOH on chromosome 3p21.3, 6p21.2, 17p13.1, and 18q21.2 are associated with treatment outcome in 65 patients with cervical cancer after radiotherapy. Tumors and normal DNA were analyzed by polymerase chain reaction (PCR) for genetic losses at 10 polymorphic microsatellite loci. The presence of HPV and its type were analyzed by PCR-based assay using the consensus primers for E6, E7, and L1 region. Mutations of the p53 gene were identified by a single-strand conformation polymorphism analysis. Chromosomes 3p21.3, 6p21.2, 17p13.1, and 18q21.2 were involved in the LOH in 23.1%, 41.5%%, 33.8%, and 23.1% of the tumors in our study, respectively. HPV-positive tumors were found in 73.8% of the patients and p53 mutation in 10.8%. The patients with LOH on chromosome 6p21.2 and 18q21.2 survived significantly shorter compared with those without LOH on chromosome 6p21.2 and 18q21.2 in both the overall survival (P = 0.006 and P = 0.007) and the disease-free survival (P = 0.005 and P = 0.008). The HPV-negative patients survived significantly shorter compared with the HPV-positive patients in both the overall survival (P = 0.01) and the disease-free survival (P = 0.04). According to multivariate analysis, HPV status (P = 0.0004, P = 0.01), LOH on 6p21.2 (P = 0.006, P = 0.02), and LOH on 18q21.2 (in both P = 0.01) is a significant predictor of both overall and disease-free survival time. The results of our study suggest that absence of HPV infection, LOH on 6p21.2, and LOH on 18q21.2 are the most important determinants of outcome of patients with cervical carcinoma after radiotherapy.

High-risk groups of patients with Stage II colon carcinoma

BACKGROUND

It is unclear whether patients with Stage II colon carcinoma should be offered adjuvant chemotherapy. Therefore, the authors analyzed the risk factors of these patients to identify high-risk subgroups who may benefit from such treatment.

METHODS

The data from 305 patients with Stage II colon carcinoma documented in the Erlangen Registry of Colorectal Carcinoma were analyzed to identify risk factors for distant metastasis and disease-related survival. The patients were divided into two subgroups: those in a low-risk group and those in a high-risk group. The data were then compared with those from 306 patients with Stage II colon carcinoma from the German Study Group for Colorectal Carcinoma (SGCRC).

RESULTS

Emergency presentation, a primary tumor site in the left colon, pT3 tumors with a depth of invasion of > 15 mm beyond the outer border of the muscularis propria, and pT4 lesions were identified as the major risk factors for Stage II colon carcinoma. On dividing patients into subgroups according to these risk factors, it was found that patients in the high-risk group had a significantly higher risk of distant metastases and a significantly lower disease-related survival rate compared with patients in the low-risk group. On analyzing the SGCRC data, the authors also found a significantly higher rate of distant metastases in the high-risk group, but the disease-related survival rate differed only marginally.

CONCLUSIONS

Among patients with Stage II colon carcinoma, it is possible to identify a high-risk group of patients who may be candidates for adjuvant chemotherapy. Stratification by the risk factors emergency presentation, tumor site, depth of tumor invasion, and surgical department should be employed in further clinical studies.

Intratumor genetic heterogeneity in advanced human colorectal adenocarcinoma

Colorectal carcinogenesis is widely accepted as one of the best-characterized examples of stepwise progression. The existing colorectal carcinogenesis model assumes genetic homogeneity of individual tumors for the main known genetic alterations: K-ras and p53 genes point mutations and loss of heterozygosity (LOH) of chromosome 5q and 18q. The object of the present study was to demonstrate the existence of an intratumor genetic heterogeneity in advanced sporadic colorectal carcinoma for these genetic alterations. Using improved tissue microdissection and DNA extraction, for each tumor, amplifiable DNA was obtained from 15 to 20 areas, of which 1 to 2 concerned lymph node metastases (LNM). This study revealed that 10 of 15 (67%) analyzed tumors were heterogeneous for at least 1 genetic alteration, with between 2 and 6 genotypically different clones detected per tumor. No correlation was observed between the genotype of these subclones and histological differentiation or invasive propensity. Intratumor heterogeneity was more frequently observed for LOH than for point mutations, 67% and 58% for LOH at APC and DCC locus, and 20% for mutation of either the K-ras or p53 gene. In 5 of the 9 (56%) heterogeneous cases with available LNM, the genotype observed in the LNM was different from that of the main clone in the primary tumor, and moreover, 2 of the LNM displayed a genotype undetected in the primary tumor. In conclusion, intratumor genetic heterogeneity was demonstrated in advanced sporadic colorectal carcinoma and was represented as topographically distinct genotypic subclones. Taking into account such a significant genetic heterogeneity of colorectal tumors, the use of genetic markers for prognosis management should be reconsidered.

Molecular predictors of survival after adjuvant chemotherapy for colon cancer

BACKGROUND

Adjuvant chemotherapy improves survival among patients with stage III colon cancer, but no reliable molecular predictors of outcome have been identified.

METHODS

We evaluated loss of chromosomal material (also called loss of heterozygosity or allelic loss) from chromosomes 18q, 17p, and 8p; cellular levels of p53 and p21(WAF1/CIP1) proteins; and microsatellite instability as molecular markers. We analyzed tumor tissue from 460 patients with stage III and high-risk stage II colon cancer who had been treated with various combinations of adjuvant fluorouracil, leucovorin, and levamisole to determine the ability of these markers to predict survival.

RESULTS

Loss of heterozygosity at 18q was present in 155 of 319 cancers (49 percent). High levels of microsatellite instability were found in 62 of 298 tumors (21 percent), and 38 of these 62 tumors (61 percent) had a mutation of the gene for the type II receptor for transforming growth factor beta1 (TGF-beta1). Among patients with microsatellite-stable stage III cancer, five-year overall survival after fluorouracil-based chemotherapy was 74 percent in those whose cancer retained 18q alleles and 50 percent in those with loss of 18q alleles (relative risk of death with loss at 18q, 2.75; 95 percent confidence interval, 1.34 to 5.65; P=0.006). The five-year survival rate among patients whose cancer had high levels of microsatellite instability was 74 percent in the presence of a mutated gene for the type II receptor for TGF-beta1 and 46 percent if the tumor did not have this mutation (relative risk of death, 2.90; 95 percent confidence interval, 1.14 to 7.35; P=0.03).

CONCLUSIONS

Retention of 18q alleles in microsatellite-stable cancers and mutation of the gene for the type II receptor for TGF-beta1 in cancers with high levels of microsatellite instability point to a favorable outcome after adjuvant chemotherapy with fluorouracil-based regimens for stage III colon cancer.

Diagnostic and prognostic tumor markers in the gastrointestinal tract

The gastrointestinal tract is the most common site of malignancies of any anatomic system in the body. An early detection of primary tumors of the bowel, pancreas, liver, stomach, and esophagus is often difficult in asymptomatic patients and for this reason these tumors are often detected at a relatively advanced stage, when symptoms lead to a diagnostic evaluation. Furthermore, gastrointestinal tract tumors have an extremely variable prognosis; thus, the identification of new prognostic parameters may be useful for selecting patients to more tailored therapies. In this work, the main molecular, genetic, tissular, and circulating tumor markers proposed for diagnosis and prognosis of gastrointestinal malignancies are reviewed and discussed.

Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999

BACKGROUND

Under the auspices of the College of American Pathologists, the current state of knowledge regarding pathologic prognostic factors (factors linked to outcome) and predictive factors (factors predicting response to therapy) in colorectal carcinoma was evaluated. A multidisciplinary group of clinical (including the disciplines of medical oncology, surgical oncology, and radiation oncology), pathologic, and statistical experts in colorectal cancer reviewed all relevant medical literature and stratified the reported prognostic factors into categories that reflected the strength of the published evidence demonstrating their prognostic value. Accordingly, the following categories of prognostic factors were defined. Category I includes factors definitively proven to be of prognostic import based on evidence from multiple statistically robust published trials and generally used in patient management. Category IIA includes factors extensively studied biologically and/or clinically and repeatedly shown to have prognostic value for outcome and/or predictive value for therapy that is of sufficient import to be included in the pathology report but that remains to be validated in statistically robust studies. Category IIB includes factors shown to be promising in multiple studies but lacking sufficient data for inclusion in category I or IIA. Category III includes factors not yet sufficiently studied to determine their prognostic value. Category IV includes factors well studied and shown to have no prognostic significance.

MATERIALS AND METHODS

The medical literature was critically reviewed, and the analysis revealed specific points of variability in approach that prevented direct comparisons among published studies and compromised the quality of the collective data. Categories of variability recognized included the following: (1) methods of analysis, (2) interpretation of findings, (3) reporting of data, and (4) statistical evaluation. Additional points of variability within these categories were defined from the collective experience of the group. Reasons for the assignment of an individual prognostic factor to category I, II, III, or IV (categories defined by the level of scientific validation) were outlined with reference to the specific types of variability associated with the supportive data. For each factor and category of variability related to that factor, detailed recommendations for improvement were made. The recommendations were based on the following aims: (1) to increase the uniformity and completeness of pathologic evaluation of tumor specimens, (2) to enhance the quality of the data needed for definitive evaluation of the prognostic value of individual prognostic factors, and (3) ultimately, to improve patient care.

RESULTS AND CONCLUSIONS

Factors that were determined to merit inclusion in category I were as follows: the local extent of tumor assessed pathologically (the pT category of the TNM staging system of the American Joint Committee on Cancer and the Union Internationale Contre le Cancer [AJCC/UICC]); regional lymph node metastasis (the pN category of the TNM staging system); blood or lymphatic vessel invasion; residual tumor following surgery with curative intent (the R classification of the AJCC/UICC staging system), especially as it relates to positive surgical margins; and preoperative elevation of carcinoembryonic antigen elevation (a factor established by laboratory medicine methods rather than anatomic pathology). Factors in category IIA included the following: tumor grade, radial margin status (for resection specimens with nonperitonealized surfaces), and residual tumor in the resection specimen following neoadjuvant therapy (the ypTNM category of the TNM staging system of the AJCC/UICC). (ABSTRACT TRUNCATED)

American Joint Committee on Cancer Prognostic Factors Consensus Conference: Colorectal Working Group

BACKGROUND

The American Joint Committee on Cancer (AJCC), which regularly reviews TNM staging systems, established a working party to develop recommendations for colorectal carcinoma.

METHODS

A multidisciplinary consensus conference using published literature developed an arbitrary classification system of prognostic marker value (Category I, IIA, IIB, III, and IV), which forms the framework for this report.

RESULTS

The working party concluded that several T categories should be subdivided: pTis into intraepithelial carcinoma (pTie) and intramucosal carcinoma (pTim); pT1 into pT1a and pT1b corresponding to the absence or presence of blood or lymphatic vessel invasion, respectively; and pT4 into pT4a and pT4b according to the absence or presence of tumor involving the surface of the specimen, respectively. The working party also recommended that TNM groups be stratified based on the presence or absence of elevated serum levels of carcinoembryonic antigen (CEA) (>/= 5 ng/mL) on preoperative clinical examination. In addition, the working party also concluded that carcinoma of the appendix should be excluded from the colorectal carcinoma staging system because of fundamental differences in natural history.

CONCLUSIONS

The TNM categories and stage groupings for colorectal carcinoma published in the current AJCC manual have clinical and academic value. However, a few categories require subdivision to provide increasing discrimination for individual patients. The serum marker CEA should be added to the staging system, whereas multiple other factors should be recorded as part of good clinical practice. Although many molecular and oncogenic markers show promise to supplement or modify the current staging systems eventually, to the authors' knowledge none have yet been evaluated sufficiently to recommend their inclusion in the TNM system.

Microsatellite instability and 8p allelic imbalance in stage B2 and C colorectal cancers

BACKGROUND

Microsatellite instability (MSI) and allelic imbalance involving chromosome arms 5q, 8p, 17p, and 18q are genetic alterations commonly found in colorectal cancer. We investigated whether the presence or absence of these genetic alterations would allow stratification of patients with Astler-Coller stage B2 or C colorectal cancer into favorable and unfavorable prognostic groups.

METHODS

Tumors from 508 patients were evaluated for MSI and allelic imbalance by use of 11 microsatellite markers located on chromosome arms 5q, 8p, 15q, 17p, and 18q. Genetic alterations involving each of these markers were examined for associations with survival and disease recurrence. All P values are two-sided.

RESULTS

In univariate analyses, high MSI (MSI-H), i.e., MSI at 30% or more of the loci examined, was associated with improved survival (P =.02) and time to recurrence (P =.01). The group of patients whose tumors exhibited allelic imbalance at chromosome 8p had decreased survival (P =.02) and time to recurrence (P =.004). No statistically significant associations with survival or time to recurrence were observed for markers on chromosome arms 5q, 15q, 17p, or 18q. In multivariate analyses, MSI-H was an independent predictor of improved survival (hazard ratio [HR] = 0.51; 95% confidence interval [CI] = 0.31-0.82; P =.006) and time to recurrence (HR = 0.42; 95% CI = 0.24-0.74; P =.003), and 8p allelic imbalance was an independent predictor of decreased survival (HR = 1.89; 95% CI = 1.25-2.83; P =. 002) and time to recurrence (HR = 2.07; 95% CI = 1.32-3.25; P =.002).

CONCLUSIONS

Patients whose tumors exhibited MSI-H had a favorable prognosis, whereas those with 8p allelic imbalance had a poor prognosis; both alterations served as independent prognostic factors. To our knowledge, this is the first report of an association between 8p allelic imbalance and survival in patients with colorectal cancer.

Expression of the deleted in colorectal cancer gene is related to prognosis in DNA diploid and low proliferative colorectal adenocarcinoma

PURPOSE

Whether or not the deleted in colorectal cancer (DCC) gene is implicated in metastases or in predicting prognosis in patients with colorectal cancer has not previously been substantiated. Our aims were to investigate DCC expression in primary colorectal cancers and in metastases to identify any prognostic significance.

PATIENTS AND METHODS

DCC expression was examined immunohistochemically in 195 primary colorectal adenocarcinomas and in 23 paired primary tumors and lymph node metastases. DNA content and S-phase fraction were measured by flow cytometry.

RESULTS

The absence of DCC expression was observed in 55 primary tumors (28%). DCC negativity was significantly related to poor prognosis in patients with DNA diploid tumors (P =.03) and those with a low S-phase fraction (< 5%, P =.02) but not in patients with nondiploid tumors or those with a higher S-phase fraction. Furthermore, DCC expression retained its prognostic significance in the diploid subgroup after adjusting for sex, age, site, stage, growth pattern, and differentiation (P =.01). DCC expression was similar in primary tumors and their metastases.

CONCLUSION

The absence of DCC predicted a poor outcome in the patients with diploid tumors and those tumors with a low S-phase fraction. Immunohistochemistry may be considered as a practical test to assess prognosis in this subgroup of patients.

Loss of heterozygosity at 18q21 is indicative of recurrence and therefore poor prognosis in a subset of colorectal cancers

Adjuvant therapies are increasingly used in colorectal cancers for the prevention of recurrence. These therapies have side-effects and should, thus, be used only if really beneficial. However, the development of recurrence cannot be predicted reliably at the moment of diagnosis, and targeting of adjuvant therapies is thus based only on the primary stage of the cancer. Loss of heterozygosity (LOH) in the long arm of chromosome 18 is suggested to be related to poor survival and possibly to the development of metastases. We studied the value of LOH at 18q21 as a marker of colorectal cancer prognosis, association with clinicopathological variables, tumour recurrence and survival of the patients. Of the 255 patients studied, 195 were informative as regards LOH status when analysed in primary colorectal cancer specimens using the polymerase chain reaction (PCR) and fragment analysis. LOH at 18q21 was significantly associated with the development of recurrence (P = 0.01) and indicated poor survival in patients of Dukes' classes B and C, in which most recurrences (82%) occurred. An increased rate of tumour recurrence is the reason for poor survival among patients with LOH at 18q21 in primary cancer. These patients are a possible target group for recurrence-preventing adjuvant therapies.

Prognostic markers in rectal carcinoma

Guidelines from two major organizations have recently supported the use of only the serological marker carcinoembryonic antigen (CEA) for the prognostication and monitoring of patients with colorectal carcinoma. However, in view of the exciting advances made recently in elucidating the molecular and cellular biology of adenocarcinoma of the rectum, the molecules that transform the well-ordered normal rectal epithelium into an invasive adenocarcinoma may yield information about the ultimate behavior of that cancer. Consequently, assessing the expression of molecules within a primary cancer may predict the probability of regional and distant metastasis, response to therapy, and outcome. This review analyzes the current state of intratumoral expression of several molecular markers for the management of rectal cancer and evaluates their potential for defining which patients may undergo rectal sphincter preservation and need adjuvant therapy.

Prognostic factors in colorectal cancer. Literature review for clinical application

PURPOSE

Identification of prognostic factors is a primary basis for planning the treatment and predicting the outcome of patients with colorectal cancer. Reviewing studies from the literature performed using univariate and multivariate analyses and their own study, the authors critically discuss the prognostic value of the clinicopathologic parameters of the tumor.

METHODS

Among 853 patients with colorectal tumors seen at the Department of Clinical Surgery of the Catholic University of Rome, Italy, 690 cases that were curatively resected the study. Overall survival rate, related to the clinicopathologic variables, was calculated, and univariate and multivariate analyses were performed.

RESULTS

Five-year and ten-year overall survival rates were 70 and 55 percent, respectively. Univariate and multivariate analyses showed that node involvement, distant metastases, bowel obstruction, and patient gender are factors independently related to outcome.

CONCLUSIONS

Data from the literature and the present study suggest that only a few clinical parameters, particularly bowel obstruction, and some pathologic factors (tumor stage, vessels invasion, and tumor ploidy) are related to patient survival rate and are the most reliable prognostic criteria. In prospective clinical studies, any other new pathologic or molecular factors should be matched with these parameters to confirm their value in outcome prediction.

Allelic loss on chromosome 18q as a prognostic marker in stage II colorectal cancer

BACKGROUND & AIMS

Loss of heterozygosity (LOH) on chromosome 18q is frequent in colorectal cancer (CRC) and has been associated with poor prognosis in stage II tumors. This study investigated the frequency of LOH in sporadic CRC and its effect on patient prognosis.

METHODS

One hundred forty-four patients were screened for LOH at 18q by polymerase chain reaction using three polymorphic microsatellite markers.

RESULTS

Nineteen patients were excluded because their tumors showed microsatellite instability in at least one marker. Of the remaining 125 patients, 121 were informative in at least one marker; 45% (54 of 121) showed 18q LOH. Five-year survival was 42% in those with 18q LOH and 73% in those without 18q LOH (P = 0.008). Multivariate analysis showed that tumor side (P = 0.0001) and 18q LOH (P = 0.01) were the only independent prognostic factors. Examining markers individually showed that only the lost of D18S474 had a significant influence on survival in patients with stage II CRC (P = 0.016).

CONCLUSIONS

18q LOH indicates an unfavorable outcome in patients with stage II CRC. Our results emphasize the importance of the 18q21.1 region, where several tumor-suppressor genes have been mapped. Microsatellite analysis may be useful in identifying high-risk patients who might benefit from adjuvant therapy.

Clinical and molecular prognostic factors in sphincter-preserving surgery for rectal cancer

As many as a third of patients with rectal cancers may be candidates for sphincter preservation surgery. The goal of the conservative management of adenocarcinoma of the distal rectum is to preserve rectal sphincter function without sacrificing local tumor control. To achieve this goal, a combined modality approach is necessary because multimodality therapy for more advanced disease has improved both local control and survival. Candidates for local excision are those with adenocarcinomas with a maximal diameter of less than 4 cm, mobile, and not poorly differentiated or mucinous and within 10 cm of the anal verge--usually within 6 cm. These criteria should be defined objectively by biopsy combined with state-of-the-art endorectal imaging. Newer molecular markers that are associated with prognosis and response to therapy may also be important for assessing prognosis, probability of local recurrence, and whether conservative treatment is appropriate. Patients with T0-3 N0 lesions meeting these standard clinicopathologic criteria have been treated successfully with wide local excision combined with chemotherapy and radiotherapy. Patients with larger or more advanced lesions may undergo low anterior resection with coloanal anastomosis. After resection, radiotherapy to at least 45 to 50 Gy is delivered to the pelvis and tumor bed often with concomitant chemotherapy. The overall rate of local failure in prospective single-institution trials in which local excision is performed with postoperative chemoradiotherapy has been 5% for T1 lesions, 7% for T2 lesions and 24% for T3 lesions. Although single-institution studies have supported the concept of conservative therapy, the safety and efficacy of this approach must still be confirmed in a multicenter, prospective trial, such as that underway in several of the cooperative oncology groups, before it may be considered a standard of practice.

Prognostic significance of DNA ploidy in patients with stage II and stage III colon carcinoma: a prospective flow cytometric study

BACKGROUND

The prognostic value of flow cytometric DNA ploidy in colorectal carcinoma has not been defined clearly. Most previous studies were conducted retrospectively using archival formalin fixed, paraffin embedded tumor samples. Conversely, few data on prospective studies employing fresh or frozen tissue specimens are available. There is general agreement that fresh/frozen material is more reliable than paraffin embedded tissue for DNA ploidy analysis by flow cytometry.

METHODS

In the current investigation we evaluated the prognostic significance of nuclear DNA content in a prospective series of 191 patients with curatively resected TNM Stage II (n = 107) or Stage III (n = 84) sporadic colon carcinomas. DNA ploidy status was assessed by flow cytometry utilizing multiple frozen tumor samples. Mean follow-up in surviving patients was 48.5 months (median, 46.9 months; range, 29-77 months). The Cox proportional hazards model was used to adjust for several clinical and pathologic covariates.

RESULTS

Of the 191 carcinomas examined, 47 (24.6%) were classified as DNA diploid and 144 (75.4%) as DNA aneuploid. DNA ploidy pattern was significantly related to tumor site (P < 0.0001), histologic type (P = 0.0002), and grade of differentiation (P = 0.009), but not to other clinical and pathologic variables. Patients with DNA diploid tumors showed a better disease free (P = 0.013) and overall survival (P = 0.021) than patients with DNA aneuploid adenocarcinomas. In particular, patients with Stage II DNA diploid tumors (n = 30) had an excellent clinical outcome, with an overall 5-year survival rate of 97%. When patients were analyzed according to the anatomic site of the tumor, a significant relationship between DNA ploidy status and disease free and overall survival was observed in the group of patients with carcinomas of the proximal colon (n = 84) (P = 0.004 and P = 0.002, respectively), but not among patients whose tumors were sited distally to the splenic flexure (n = 107). In multivariate analysis, nuclear DNA content was demonstrated to be an independent prognostic variable for both disease free and overall survival. Furthermore, in the group of patients with tumors of the proximal colon, DNA ploidy pattern was the single most important prognostic factor.

CONCLUSIONS

Our results confirm that flow cytometric DNA ploidy status is a significant and independent prognostic factor in patients with colon carcinoma. These findings may have clinical implications for the management of affected patients, especially those with Stage II disease.

Genetic detection of colorectal cancer cells in circulation and lymph nodes

PURPOSE

This study was undertaken to investigate the clinical implications of detection of genetic alterations in blood and lymph nodes in colorectal cancer patients.

METHODS

The reverse transcriptase polymerase chain reaction product of the cytokeratin gene in blood was examined as a cancer cell-specific expression in 35 colorectal cancer patients. The K-ras or p53 gene mutations in the lymph nodes histopathologically negative for metastasis were studied by the mutant-allele-specific amplification method in 26 colorectal cancer patients.

RESULTS

The reverse transcriptase polymerase chain reaction assay was able to detect a cytokeratin reverse transcriptase polymerase chain reaction product at a concentration from a single to ten colon cancer cells per 10(6) normal peripheral blood mononuclear cells. Cytokeratin reverse transcriptase polymerase chain reaction products were detected in nine patients' blood samples, although none of the samples were cytologically detectable. The blood's cytokeratin positivity correlated with the invasive mode of the tumor (P < 0.05) and the presence of distant metastasis (P < 0.01). Two (50 percent) of four patients whose blood was positive for cytokeratin had recurrences. Of 17 patients with the K-ras or p53 gene mutation in primary tumors, 9 (53 percent) had the corresponding mutations in lymph nodes. Mutation positivity in lymph nodes correlated with the presence of lymphatic invasion of the primary tumor (P < 0.05). All patients with mutation-negative lymph nodes remained disease-free for more than two years after surgery.

CONCLUSION

Detection of cytokeratin reverse transcriptase polymerase chain reaction products in the blood and K-ras or p53 gene mutations in the lymph nodes histologically negative for metastasis may be applicable for clinical use, despite some limitations, and may serve as a useful clinical factor for stratifying patients who are at high or low risk for recurrence after surgery.

Molecular biology of colorectal cancer

Colorectal cancer is a significant cause of morbidity and mortality in Western populations. This cancer develops as a result of the pathologic transformation of normal colonic epithelium to an adenomatous polyp and ultimately an invasive cancer. The multistep progression requires years and possibly decades and is accompanied by a number of recently characterized genetic alterations. Mutations in two classes of genes, tumor-suppressor genes and proto-oncogenes, are thought to impart a proliferative advantage to cells and contribute to development of the malignant phenotype. Inactivating mutations of both copies (alleles) of the adenomatous polyposis coli (APC) gene--a tumor-suppressor gene on chromosome 5q--mark one of the earliest events in colorectal carcinogenesis. Germline mutation of the APC gene and subsequent somatic mutation of the second APC allele cause the inherited familial adenomatous polyposis syndrome. This syndrome is characterized by the presence of hundreds to thousands of colonic adenomatous polyps. If these polyps are left untreated, colorectal cancer develops. Mutation leading to dysregulation of the K-ras protooncogene is also thought to be an early event in colon cancer formation. Conversely, loss of heterozygosity on the long arm of chromosome 18 (18q) occurs later in the sequence of development from adenoma to carcinoma, and this mutation may predict poor prognosis. Loss of the 18q region is thought to contribute to inactivation of the DCC tumor-suppressor gene. More recent evidence suggests that other tumor-suppressor genes--DPC4 and MADR2 of the transforming growth factor beta (TGF-beta) pathway--also may be inactivated by allelic loss on chromosome 18q. In addition, mutation of the tumor-suppressor gene p53 on chromosome 17p appears to be a late phenomenon in colorectal carcinogenesis. This mutation may allow the growing tumor with multiple genetic alterations to evade cell cycle arrest and apoptosis. Neoplastic progression is probably accompanied by additional, undiscovered genetic events, which are indicated by allelic loss on chromosomes 1q, 4p, 6p, 8p, 9q, and 22q in 25% to 50% of colorectal cancers. Recently, a third class of genes, DNA repair genes, has been implicated in tumorigenesis of colorectal cancer. Study findings suggest that DNA mismatch repair deficiency, due to germline mutation of the hMSH2, hMLH1, hPMS1, or hPMS2 genes, contributes to development of hereditary nonpolyposis colorectal cancer. The majority of tumors in patients with this disease and 10% to 15% of sporadic colon cancers display microsatellite instability, also know as the replication error positive (RER+) phenotype. This molecular marker of DNA mismatch repair deficiency may predict improved patient survival. Mismatch repair deficiency is thought to lead to mutation and inactivation of the genes for type II TGF-beta receptor and insulin-like growth-factor II receptor. Individuals from families at high risk for colorectal cancer (hereditary nonpolyposis colorectal cancer or familial adenomatous polyposis) should be offered genetic counseling, predictive molecular testing, and when indicated, endoscopic surveillance at appropriate intervals. Recent studies have examined colorectal carcinogenesis in the light of other genetic processes. Telomerase activity is present in almost all cancers, including colorectal cancer, but rarely in benign lesions such as adenomatous polyps or normal tissues. Furthermore, genetic alterations that allow transformed colorectal epithelial cells to escape cell cycle arrest or apoptosis also have been recognized. In addition, hypomethylation or hypermethylation of DNA sequences may alter gene expression without nucleic acid mutation.

Experimental chemotherapeutic agents for the treatment of colorectal carcinoma

Colorectal cancer is the third leading cause of cancer mortality for men and women in the United States. For the past 40 years fluorouracil has been the only agent with significant activity in this disease. More recently, advances in our understanding of the molecular biology of cancer have permitted the development of effective new agents for this disease. This article examines the current and future status of these new agents.

Prognostic significance of Bcl-2 expression and p53 nuclear accumulation in colorectal adenocarcinoma

The products of bcl-2 and p53 genes are involved in the regulation of apoptosis and proliferation and have been associated with prognosis in several malignancies, including colorectal adenocarcinoma. Although 2 European studies have reported a prognostic significance of Bcl-2 expression in colorectal adenocarcinomas, a study from the United States did not observe such an association. Therefore, we used immunohistochemistry to evaluate the prognostic significance of Bcl-2 expression, p53 nuclear accumulation and their concomitant expression in 134 US patients with colorectal adenocarcinoma. Antigen retrieval was required for adequate detection of Bcl-2 expression. Fifty percent of the colorectal tumors were classified as expressing Bcl-2, and Bcl-2 expression was associated with longer patient survival. Antigen retrieval was not necessary for detecting nuclear accumulation of p53 by immunohistochemistry. Nuclear accumulation of p53 was detected in 44% of colorectal adenocarcinomas and was associated with decreased patient survival. Tumors that did not express detectable levels of Bcl-2 but exhibited nuclear accumulation of p53 were associated with the shortest patient survival (log rank, p = 0.001). Multivariate Cox regression analysis demonstrated that Bcl-2 expression (p = 0.018), p53 nuclear accumulation (p = 0.024) and regional lymph-node metastasis (p = 0.005) were independent prognostic factors. Although a trend toward an inverse correlation between Bcl-2 and p53 expression was observed, the prognostic value of Bcl-2 expression was independent of p53 status. Thus, assessment of both Bcl-2 and p53 status may be valuable in predicting the prognosis of patients with colorectal adenocarcinomas.

Involvement of carbohydrate antigen sialyl Lewis(x) in colorectal cancer metastasis

PURPOSE

Recognition of metastatic tumor cells with distinct biochemical phenotypes predominant in the primary tumors should be useful not only for establishment of new therapeutic approaches but also for identification of high-risk or low-risk patients for relapse. We examined whether carbohydrate antigens, sialyl Lewis(x) (sLe(x)) and sialyl Lewis(a) (sLe(a)) are involved in colorectal cancer metastasis.

METHODS

Metastatic abilities of human colon cancer cell variants that were selected for their high or low cell surface levels of sLe(x) (KM12-HX and KM12-LX, respectively) were analyzed. Also, immunohistochemical expressions of sLe(x) and sLe(a) in 159 primary colorectal cancers were examined to determine the clinical significance of increased expression of these antigens.

RESULTS

KM12-HX cells adhered more readily to tumor necrosis factor-alpha activated endothelial cells than did KM12-LX cells. Increased adhesion of KM12-HX cells to activated endothelial cells was inhibited by antibodies against E-selectin and sLe(x) and by modification of cell surface carbohydrates. KM12-HX cells showed more invasive ability in vitro and more metastatic potential in the liver of nude mice than KM12-LX cells. Although no difference was seen in the expression of six messenger ribonucleic acids corresponding to progression or metastasis of colorectal cancer, expression of fucosyltransferase was found to be responsible for the higher expression of sLe(x) in KM12-HX cells. Clinical records of patients showed that disease-free survival rate of patients with sLe(x)-positive tumors was significantly poorer than that of those with sLe(x)-negative tumors. Cox's multivariate analysis revealed that the sLe(x) status was an independent predictive factor for disease recurrence (P = 0.004), depth of invasion (P = 0.0005), and histologic type (P = 0.037), but sLe(a) status, age, gender, tumor location, N stage, and vessel invasion were not.

CONCLUSION

Increased expression of sLe(x) could be involved in establishment of colorectal cancer metastasis. It appears that examining sLe(x) expression may serve as a potent marker of the recurrence in patients with colorectal cancer.

Association between sucrase-isomaltase and p53 expression in colorectal cancer

BACKGROUND

Sucrase-isomaltase (SI) is a tissue-based phenotypic marker that is an independent prognostic factor in colorectal cancer (CRC). DF3 and galectin 3 are two other tissue-based markers that are upregulated during neoplastic transformation. Because p53 mutations are acquired during neoplastic progression, we reasoned that alterations in SI and p53 may be associated despite an apparent lack of biological interaction.

METHODS

Paraffin sections from 183 patients who underwent surgery at New England Deaconess Hospital (NEDH) between 1965 and 1977 were analyzed first by immunohistochemistry (IHC) for the expression of the markers SI, DF3, and galectin 3, which were scored as absent or present. Paraffin sections from a second group of 59 patients who underwent surgery at NEDH between 1985 and 1992 were analyzed by IHC for the expression of p53 as well as SI, DF3, and galectin 3. p53 nuclear staining was scored as absent or present. Previous work has shown that p53 is mutated in all cells with nuclear staining and in 10% of tumors that are unstained.

RESULTS

SI expression was not associated with the expression of either DF3 or galectin 3, and neither DF3 nor galectin 3 were prognostic factors in CRC. None of the phenotypic markers were associated with any of the clinicopathologic variables. However, 21 of 24 p53-positive cases (88%) expressed SI, whereas 15 of 35 p53-negative cases (43%) were also SI negative (p = 0.02, Fisher exact test). p53 expression was not associated with expression of DF3 or galectin 3.

CONCLUSIONS

SI expression and p53 mutation are associated significantly in CRC. Although the mechanism underlying such an association in presently unknown, the association may define a subset of patients with a worse prognosis.

Contribution of plasminogen activators and their inhibitors to the survival prognosis of patients with Dukes' stage B and C colorectal cancer

Despite the advances in pre-, peri- and post-operative medical care of colorectal carcinoma patients, the prognosis has improved only marginally over recent decades. Thus, additional prognostic indicators would be of great clinical value to select patients for adjuvant therapy. In previous studies we found that colorectal carcinomas have a marked increase of the urokinase-type of plasminogen activator (u-PA), and the inhibitors PAI-1 and PAI-2, whereas the tissue-type plasminogen activator (t-PA) is found to be decreased in comparison with adjacent normal mucosa. In the present study we evaluated the prognostic value of several plasminogen activation parameters, determined in both normal and carcinomatous tissue from colorectal resection specimens, for overall survival of 136 Dukes' stage B and C colorectal cancer patients, in relation to major clinicopathological parameters. Uni- and multivariate analyses indicated that a high PAI-2 antigen level in carcinoma, a low t-PA activity and antigen level and a high u-PA/t-PA antigen ratio in adjacent normal mucosa are significantly associated with a poor overall survival. A high ratio of u-PA antigen in the carcinomas and t-PA antigen in normal mucosa, i.e. u-PA(C)/t-PA(N), was found to be predictive of a poor overall survival as well. All these parameters were found to be prognostically independent of the clinicopathological parameters. Multivariate analysis of combinations of these prognostically significant plasminogen activation parameters revealed that they are important independent prognostic indicators and have in fact a better prognostic value than their separate components. Based on these combined parameters, subgroups of patients with Dukes' stage B and C colorectal cancer could be identified as having either a high or a low risk regarding overall survival. In conclusion, these findings emphasize the relevance of the intestinal plasminogen activation system for survival prognosis of patients with colorectal cancer and, in the future, might constitute a patient selection criterion for adjuvant therapy.

Stromal tenascin distribution as a prognostic marker in colorectal cancer

A total of 169 colorectal adenocarcinomas, obtained from patients with a median follow-up of 6.5 years, were studied with immunohistochemical staining on cryosections using a monoclonal anti-tenascin antibody to evaluate the possible association between the staining patterns and tumour stage, tumour differentiation and survival. We found two different staining patterns in the tumour stroma--a diffuse stromal fibrillar staining in 92 out of 169 (54%) tumours and a subglandular staining in the remaining 77 tumours. When the entire group of patients (P < 0.01) and the group of potentially cured patients (P < 0.03) were analysed univariately, it was found that diffuse stromal fibrillar staining was associated with a shorter survival time than subglandular staining. In a multivariate analysis, the Dukes' stage and age were independent prognostic factors, whereas the tenascin expression did not retain a clear independent relationship to survival (P = 0.06). Hence, it appears that the tumour expression of tenascin may be a potential prognostic marker in colorectal cancer, in so far as a diffuse stromal fibrillar staining pattern seems to indicate an increased risk of poor outcome. However, after adjustment for age and Dukes' stage, the additional prognostic value of tenascin remains to be established in further analyses.

The DCC protein and prognosis in colorectal cancer

BACKGROUND

Allelic loss of chromosome 18q predicts a poor outcome in patients with stage II colorectal cancer. Although the specific gene inactivated by this allelic loss has not been elucidated, the DCC (deleted in colorectal cancer) gene is a candidate. We investigated whether the expression of the DCC protein in tumor cells is a prognostic marker in colorectal carcinoma.

METHODS

The expression of DCC was evaluated immunohistochemically in 132 paraffin-embedded samples from patients with curatively resected stage II and III colorectal carcinomas. The Cox proportional-hazards model was used to adjust for covariates including age, sex, tumor site, degree of tumor differentiation, and use of adjuvant therapy.

RESULTS

The expression of DCC was a strong positive predictive factor for survival in both stage II and stage III colorectal carcinomas. In patients with stage II disease whose tumors expressed DCC, the five-year survival rate was 94.3 percent, whereas in patients with DCC-negative tumors, the survival rate was 61.6 percent (P<0.001). In patients with stage III disease, the respective survival rates were 59.3 percent and 33.2 percent (P=0.03).

CONCLUSIONS

DCC is a prognostic marker in patients with stage II or stage III colorectal cancer. In stage II colorectal carcinomas, the absence of DCC identifies a subgroup of patients with lesions that behave like stage III cancers. These findings may thus have therapeutic implications in this group of patients.

Prognostic significance of p53 overexpression and mutation in colorectal adenocarcinomas

The p53 tumour-suppressor gene is found altered in the majority of colorectal cancers. Lesions include allelic loss, mutation of the gene and overexpression of the p53 protein. All of these lesions have been analysed for prognostic significance, and whereas both mutation and allelic loss have been shown to be reasonably useful markers of prognosis, the utility of overexpression of the p53 protein is more ambiguous. Given that many authors use p53 overexpression as a marker for point mutation this issue is of some importance. We have therefore examined 100 colorectal carcinomas for mutation of the p53 gene, as well as overexpression of the p53 protein. Results show that whereas mutation of the p53 gene is associated with p53 overexpression, the degree of association depends, at least in part, upon the particular antibody used. Moreover, although mutation of the p53 gene does provide prognostic information, overexpression of the p53 protein, as detected with two antibodies, does not. These results suggest that immunohistochemistry is not a suitable alternative to direct detection of mutation in assessing prognosis in colorectal cancer patients.

Adjuvant treatment of colon and rectal cancer: impact of chemotherapy, radiotherapy, and immunotherapy on routine postsurgical patient management. Forschungsgruppe Onkologie Gastrointestinaler Tumoren (FOGT)

Colon cancer patients with UICC stage III or T4 N0 M0 stage II should receive postoperative adjuvant therapy, since relapse rates are high and surgical outcome has been improved by adjuvant treatment. The standard treatment is 5-fluourouracil plus levamisole; an alternative option is the combination of 5-fluourouracil and folinic acid. Stage II (T3 N0 M0) colon cancer patients should not receive adjuvant treatment outside of studies. Rectal cancer patients of stage II or III should receive postoperative radiochemotherapy with 45-54.4 Gy and 5-fluourouracil as standard treatment. Patients not eligible for radiotherapy may receive adjuvant chemotherapy only. Studies need to be conducted to improve adjuvant therapy in colorectal cancer. All qualified patients should be treated within these studies requiring sufficient patient numbers, as well as comparable surgical procedures, proper patient selection and stratification criteria, drug and dose intensities. Intraportal infusion may be as effective as systemic adjuvant treatment; the tumor type and stage for which benefit from this kind of treatment is consistently significant needs to be defined, since intraportal infusion of all resectable colorectal cancers is overtreatment. Both surgery and histopathological staging may be improved in some centers, and these require standardization and quality control.

p53 nuclear overexpression may not be an independent prognostic marker in early colorectal cancer

PURPOSE

This study was designed to determine if p53 nuclear overexpression, as detected by immunohistochemistry, is a marker of prognostic significance in early (Stage I) colorectal cancer (CRC).

METHODS

Tissue sections obtained from archival blocks of 66 patients with surgically treated Stage 1 CRC were stained immunohistochemically for p53 using a monoclonal antibody (PAB 1801-Ab2). Differences in survival between p53 positive (p53+) and p53 negative (p53-) groups were compared using Kaplan-Meier survival curves and the log-rank test.

RESULTS

Thirty-four patients (51.5 percent) were p53+ and 32 (48.5 percent) were p53-. There were significantly more p53+ tumors in females (23 of 34) compared with males (11 of 34) (P = 0.01). Follow-up ranged from 1 to 128.5 (mean, 44.7; median, 38.2) months. Thirteen patients (19.7 percent) developed recurrence, of whom five died of disease. Univariate analysis of clinical and pathologic variables did not reveal my statistically significant differences between p53+ and p53- tumors. Mean actuarial survival was longer (48.2 months) in the p53- group compared with the p53+ group (41.5 months). However, comparison of survival curves using the log-rank test did not show a statistically significant difference in survival (log-rank chi-squared = 0.2; P = 0.6).

CONCLUSION

p53 nuclear overexpression does not appear to be an independent marker of prognostic significance in surgically treated early CRC. Females were more likely to have p53+ tumors. The biologic significance of this findings is unknown.

Inducibility of endogenous tumor necrosis factor by tumor cells from colorectal tumor patients at Dukes stage C as a novel prognostic factor following curative operation

PURPOSE

It is well known that tumor cells secrete endogenous tumor necrosis factor (en-TNF) as a cytokine when stimulated with lipopolysaccharide (LPS). We, therefore, analyzed the biologic role of en-TNF secreted by tumor cells themselves to learn the prognosis of patients and the susceptibility of tumors to biologic response modifiers in particular.

METHODS

Patients with Dukes C colorectal tumors were studied after curative operation to determine the inducibility of en-TNF by their primary cultured cells in response to LPS.

RESULTS

Irrespective of the known clinicopathologic factors of the tumors, en-TNF was produced in 21 of a total of 44 patients. The group of patients with clear en-TNF production showed a significantly lower incidence of recurrence and/or metastasis and a higher survival rate than the group without en-TNF production, suggesting a strong correlation between patient prognosis and inducibility of en-TNF.

CONCLUSION

Inducibility of en-TNF by tumor cells themselves can be a novel prognostic factor for patients with colorectal tumor, especially of Dukes Stage C.

The common molecular genetic alterations in Dukes' B and C colorectal carcinomas are not short-term prognostic indicators of survival

Our study was undertaken to determine the prognostic significance of several common genetic alterations observed in colorectal carcinomas. We have previously analysed loss of heterozygosity of the MCC, APC, p53 and DCC tumour suppressor gene loci as well as p53 gene mutations and protein over-expression in a series of 100 Dukes' stage B and C colorectal tumours obtained at surgery. To extend our observations of alterations that may occur in these tumours, mutations to the c-Ki-ras oncogene and APC tumour suppressor gene were detected by PCR single-strand conformation polymorphism analysis. Short-term follow-up revealed no significant association between overall patient survival and any single, or combination of, genetic alteration(s). Surprisingly, patients whose tumours showed evidence of p53 protein over-expression/accumulation by immunocytochemistry (ICC) had a significantly better prognosis (p = 0.039) than those whose tumours had no p53 ICC reactivity.

Comparison of p53 gene mutation and protein overexpression in colorectal carcinomas

Immunocytochemistry (ICC) has been used routinely to stain for p53 overexpression in a range of human tumours. The underlying assumption has been that positive staining indicates a mutation in the p53 coding sequence. Recently, however, discordancy has been observed and the accuracy of ICC as a marker of p53 gene mutation has been questioned. In this study of 109 colorectal adenocarcinomas, we compared ICC staining with p53 gene mutations detected by single-strand conformation polymorphism (SSCP) analysis. Concordancy between the two techniques was found in 69% of tumours. ICC-positive/SSCP-negative cases accounted for 20% of tumours and ICC-negative/SSCP-positive cases for the remaining 11%. These results caution against the assumption that p53 protein overexpression is always associated with a gene mutation. Epigenetic phenomena may account for a significant proportion of ICC-positive tumours.

Expression of autocrine motility factor receptor in colorectal cancer as a predictor for disease recurrence

BACKGROUND

New biologic prognostic factors are needed to guide the treatment of patients with colorectal cancer. The prognostic value of the altered expression of the cell surface glycoprotein gp78, which has been implicated in tumor-cell invasion and metastasis as an autocrine motility factor (AMF) receptor, was evaluated.

METHODS

The level of expression of AMF receptor gp78 was analyzed immunohistochemically in tumor specimens from 118 patients who had undergone surgery for colorectal cancer. Multivariate analysis was used to determine whether gp78 expression status was correlated with patient prognosis.

RESULTS

Among the 118 patients studied, the 5-year survival rate for the 51 patients who had gp78-positive tumors was significantly poorer that that of the 67 patients who had gp78-negative tumors (49.8% vs. 89%). The incidence of gp78 positivity was correlated with tumor progression as reflected by histologic type, depth of invasion, lymph node metastasis, vessel invasion, and tumor stage. Among the 101 patients who underwent curative resection, the difference in disease free survival between patients with gp78-positive tumors and those with gp78-negative tumors was significant. This significant difference remained among patients who had Stage II tumors. Multivariate analysis with the Cox regression model indicated that gp78 positivity was a good predictor of disease recurrence, ranking with extent of tumor invasion (T classification) and lymph node status (N classification).

CONCLUSIONS

Increased expression of gp78 is correlated with a high incidence of recurrence and, consequently, with decreased survival of patients with colorectal cancer. Expression of gp78 might be of prognostic value in these patients.

Allelic loss of chromosome 18q and prognosis in colorectal cancer

BACKGROUND

Colorectal cancer occurs in approximately 150,000 people each year in the United States. Prognostic assessment influences the treatment of patients with colorectal cancer, including decisions about adjuvant therapy. We evaluated chromosome 18q allelic loss, a genetic event associated with tumor progression, as a prognostic marker for this disease.

METHODS

We developed procedures to examine the status of chromosome 18q with microsatellite markers and DNA from formalin-fixed, paraffin-embedded tumors. Allelic loss of chromosome 18q was assessed in 145 consecutively resected stage II or III colorectal carcinomas.

RESULTS

Among patients with stage II disease, the five-year survival rate was 93 percent in those whose tumor had no evidence of allelic loss of chromosome 18q and 54 percent in those with allelic loss; among patients with stage III disease, survival was 52 and 38 percent, respectively. The overall estimated hazard ratio for death in patients whose tumor had chromosome 18q allelic loss was 2.83 (P = 0.008) according to univariate analysis. Furthermore, chromosome 18q allelic loss remained a strong predictive factor (hazard ratio for death, 2.46; 95 percent confidence interval, 1.06 to 5.71; P = 0.036) after adjustment for all other evaluated factors, including tumor differentiation, vein invasion, and TNM stage.

CONCLUSIONS

The status of chromosome 18q has strong prognostic value in patients with stage II colorectal cancer. The prognosis in patients with stage II cancer and chromosome 18q allelic loss is similar to that in patients with stage III cancer, who are thought to benefit from adjuvant therapy. In contrast, patients with stage II disease who do not have chromosome 18q allelic loss in their tumor have a survival rate similar to that of patients with stage I disease and may not require additional therapy.