Flow cytometric examination of p53 protein in primary tumors and metastases to the liver and lymph nodes of colorectal cancer

PURPOSE AND METHODS: To confirm prognostic significance of overexpression of p53 in cases of colorectal cancer, expression of p53 protein was examined by flow cytometry in 113 cases of colorectal cancer and its metastasis to the liver and lymph nodes. RESULTS: Overexpression of p53 was found in 44 (39 percent) of the 113 primary tumors. There were no significant correlations among the level of p53 protein in the primary tumor, clinicopathologic features, and prognosis of colorectal cancer. Overexpression of p53 protein was detected in 72 percent (18/25) of liver metastases and in 40 percent (10/25) of lymph node métastases. Frequency of samples that were positive for p53 was significantly higher for liver metastases than for primary tumors and lymph node metastases (P<0.01). By comparing overexpression of p53 in primary tumors with that in corresponding secondary tumors, a decrease of more than 5 percent in the fluorescence index, compared with primary tumor, was not found in liver metastasis but was found in 20 percent of lymph node metastases. Incidence of cases with lower level expression of p53, compared with primary tumor, was significantly higher in lymph node metastases (32 percent) than in liver metastases (8 percent;P<0.05). CONCLUSIONS: From these results, it seems possible that overexpression of p53 may not be a good prognostic indicator of colorectal cancer and may be influenced by environments of the tumor.Presented at the meeting of the Japanese Gastroenterological Surgery, Fukui City, Japan, July 20 and 21, 1995.     

Colorectal carcinoma prognosis can be predicted by alterations in gene <Emphasis Type="Italic">p53</Emphasis> exons 5 and 8

Background and aims Gene p53 alteration is a genetic event described in the progression from adenoma to colorectal carcinoma. Most of the p53 mutations occur in exons 5 to 8 in highly preserved regions and in the three main structural domains of the p53 protein. It is possible that mutations affecting different structural regions may present different effects on the p53 protein function and, due to this, they may have different prognostic meaning. Materials and methods The study population consisted of 353 patients diagnosed with sporadic colorectal cancer. Mutations in 5–8 exons of p53 gene were detected by means of single strand conformation polymorphism (SSCP). All samples that showed different migration bands in SSCP were confirmed by sequencing. Results A total of 69 patients (19.7%) showed alterations of the gene p53. It was observed that mutation in codon 175 in exon 5 was related to tumors located in the colon (p = 0.01) and the mutation in the codon 288 in exon 8 was related to rectal tumors (p = 0.02). In the study of overall survival, mutation in codon 175 of exon 5 conferred a better prognosis and alterations of exon 8 were related to a worse prognosis in different population subgroups: in men, in patients younger than 71 years old, in the tumors located in the proximal colon, the ones moderately differentiated, and those that are mucinous. Conclusion According to this study, mutations in different exons of p53 are related to different phenotypes in colorectal cancer. These phenotypes could mean differences in the clinical evolution of the patients. This study was supported by grant no. PI030514 from the Fondo de Investigaciones Sanitarias, Spain.     

Prevalence of Serum p53 Antibodies against Tumor p53 Protein in Colorectal Cancer

Background: Genetic events associated to colorectal carcinoma are well characterized, but there is scanty information about this issue in Egyptian subjects. The aim of this study was to investigate tissue p53 overexpression in paraffin embedded tumor and serum p53 antibodies in colorectal cancer patients with special reference to patient outcome.Patients and Methods: The study was conducted to 135 consecutive colorectal cancer patients. The tumor p53 protein was overexpressed in 60% and serum p53 antibodies in 35%, also tumor p53 accumulation is not necessarily associated with serum p53 antibodies positive cases. Tumor p53 overexpression was more frequent in distal colorectum than in proximal tumor (63.7% vs 41%) (p > 0.05).Results: Both tumor p53 overexpression and serum p53 antibodies increased signficantly with the stage of the tumor and lymph node involvement, but not with the grade, histopathological types and other histologic parameters. After a follow-up of 5 years, in the Kaplan Meier univariate analysis the factors stage (p = 0.0004), tumor p53 immunostaining (p < 0.0001) and serum p53 antibodies (p < 0.04) had a prognostic value.Conclusion: In conclusion p53 overexpression was associated with advanced histopathological stage and a high risk of recurrence.     

hTERT expression in colorectal adenocarcinoma: correlations with p21, p53 expressions and clinicopathological features

Background The clinicopathological roles and relationships of hTERT, p21 and p53 proteins have not been studied in depth in colorectal cancer. The aim of the present study is to investigate the clinicopathological roles of expression of hTERT protein expression and its relationship with the expression of p21 and p53 proteins in a large cohort of patients with colorectal adenocarcinoma. Materials and methods Expressions of hTERT, p21 and p53 proteins were investigated in 188 patients with colorectal adenocarcinomas by immunohistochemistry. The findings were correlated with the clinicopathological features and survival data of colorectal adenocarcinomas. Results hTERT, p53 and p21 proteins were detected in 63%, 100% and 62% of the patients with colorectal carcinoma. High level of hTERT protein expression was noted in patients with metastases (p = 0.038) and in patients with rectal cancer (p = 0.046). Loss or low level of p21 protein was often noted in non-mucinous colorectal adenocarcinoma when compared with mucinous adenocarcinoma (p = 0.001). Furthermore, p53 expression was more frequently noted in non-mucinous adenocarcinoma (p = 0.001). The level of expression of p21 protein was positively correlated with expression of level of hTERT protein (p = 0.00001). The survival of the patients was related to staging (p = 0.001) and p53 protein expression (p = 0.038) of the tumours. Conclusions hTERT protein expression is an indicator of the biological aggressiveness of the cancer. The level of expression of the protein was also related to the distal location and level of p21 expression of the tumours.     

Immunoreactivity evaluation of mutant p53 gene product with DNA ploidy pattern in colorectal carcinoma

BACKGROUND/AIMS: Studying p53 protein expression in tumor cells is one of the effective methods for detecting p53 gene mutations. This study attempted simultaneous monitoring of p53 overexpression in colon cancer using immunohistochemical and immunoblotting techniques and also to compare abnormalities of p53 with DNA ploidy and clinicopathological variables. METHODOLOGY: The occurrence of p53 protein expression was analyzed in forty-nine fresh colorectal cancer specimens by immunohistochemical and p53 protein expression also demonstrated by Western immunoblotting technique in 28 colorectal cancer specimens, using an anti-human p53 monoclonal antibody (Do-7), and 25 normal colon mucosa as a negative control. DNA ploidy in 36 specimens of colon cancer tissues was determined by Flow cytometry. RESULTS: Overexpression of p53 protein was detected immunohistochemically in 53.1% (26 of 49) of the tumor specimens. DNA ploidy was performed in 36 cases, 55.6% (20 of 36) of colon cancer specimens were DNA aneuploidy, p53 immunostaining was positive in 60% of cases with DNA aneuploidy compared to 31.3% in diploid tumors (p<0.001). There was no significant association between p53 immunostaining and clinicopathological variables. Overexpression of p53 protein was demonstrated in nuclear protein extract by immunoblotting in 75% (21 of 28) of colorectal carcinoma. Aneuploidy carcinomas were more frequently p53 positive by immunoblotting than DNA diploidy carcinomas; 76.5% (13 of 17) vs. 72.7% (8 of 11) (p<0.2). P53 expression by immunoblotting was more frequently found in good lymphocytic infiltration than moderate and poor lymphocytic infiltration (p<0.001). Also, p53 expression in right colon was significant with rectum (p<0.009). The incidence of p53 expression in Duke's stage B was significant if compared with Duke's stage C (p<0.005). Immuno-reactivity of p53 expression was detected by immunostaining and immunoblotting in 89.3% (25 of 28) of colorectal cancer. P53 immunoreactivity by immunostaining and immunoblotting were closely related to the clinicopathological variables such as pathological type (p<0.01), lymphocytic infiltration (p<0.0001), tumor grade, and tumor site (p<0.001). DNA aneuploidy was more frequently p53 positive than DNA diploid tumor by immunostaining and immunoblotting (p<0.001). CONCLUSIONS: Immunohistochemistry confirmed by immunoblotting assay is a sensitive method for detecting the trace amount of p53 protein and provides valuable information for the understanding of colorectal cancer biology.     

Colorectal cancer in a population with endemic Schistosoma mansoni: is this an at-risk population?

Purpose Chronic infection with schistosomiasis has been clearly associated with the development of bladder cancer, and infestation is associated with a high incidence of colorectal cancer in endemic populations. Despite this association, the potential role of alterations in tumor suppressor genes colorectal cancers has never been evaluated in an endemically infected population. The aim of this paper was to compare histopathologic and genetic changes in schistosomal colitis-associated colorectal cancer (SCC) with colorectal cancer in a group of patients from the same population not affected by the disease (NDCC). Materials and methods Sixty patients were included in this study: SCC—40, NDCC—20. Data collected included age, sex, clinical presentation, presence of synchronous tumors, histopathology, and clinical stage. p53, DCC (deleted in colorectal cancer gene), and mismatch repair genes (MLH1 and MSH2) were studied using immunohistochemical staining. Results Patients with SCC were significantly younger than the NDCC group (34.52±11.22 years vs 50.73±12.75 years, p=0.02). Mucinous adenocarcinoma occurred significantly more frequently in SCC (35 vs 10%, p=0.02). SCC tumors were more frequently stage III or IV, and significantly more synchronous tumors were present in the affected group (SCC—8/40 vs NDCC—1/20, p=0.05). p53 staining was far more frequent in SCC (SCC—32/40 vs NDCC—8/20, p=0.006). DCC expression was similar in two groups. There were only four cases, three in SCC and one in NDCC, that showed microsatellite instability. Conclusion The data suggest that schistosomal colitis is more commonly associated with earlier onset of multicentric colorectal cancer, high percentage of mucinous adenocarcinoma, and presents at an advanced stage. The identification of a higher incidence of altered p53 expression in the SCC group raises the possibility of an association between schistosomiasis and alterations in p53 activation as an inciting event in colorectal cancer development.     

Clinical role of Bcl-2, Bax, or p53 overexpression in peripheral T-cell lymphomas

Apoptosis pathways are known to be involved in the pathogenesis of peripheral T-cell lymphomas (PTCLs). As such, the current study attempted to investigate the overexpression of Bcl-2, Bax, or p53 with respect to the progression of PTCL. Paraffin-embedded specimens from 74 patients were analyzed immunohistochemically for Bcl-2, Bax, or p53 overexpression including PTCL-unspecified (n=45), extranodal natural killer cell/T-cell lymphoma (n=10), angioimmunoblastic T-cell lymphoma (n=7), anaplastic large cell lymphoma (n=7), and cutaneous T-cell lymphoma (n=5). The Bcl-2 overexpression was exhibited in 33 (45%), Bax, 17 (23%), and p53, 33 patients (45%). Bcl-2 overexpression was strongly associated with advanced stage (p=0.021) and higher international prognostic indices (IPI) (p=0.038). Bcl-2⁺/p53⁺ group was found to be associated with advanced stage (p=0.008) and higher IPI (p=0.001), compared with the other groups. The independent expression of Bcl-2 or p53 was not correlated with survival. Meanwhile, when confined to Bcl-2 overexpressing groups, p53 overexpression was significantly associated with poor survival (p=0.05), as the 3-year OS rate was 82.5% for Bcl-2⁺/p53- cases, yet only 32.9% for Bcl-2⁺/p53⁺ cases. Multivariate analyses for OS found the Bcl-2/p53 co-expression (p=0.004) as independent prognostic factor, together with advanced stage (p<0.001) and higher prognostic index for PTCL (p=0.008). Bcl-2 overexpression seemed to correlate with the progression of PTCL interacting with a p53-dependent pathway.     

Clinicopathologic evaluation of the trend toward histologically poor differentiation with submucosal invasion in superficial early colorectal adenocarcinomas

We examined differences in the degree of differentiation in intramucosal and submucosal areas of involvement in early colorectal adenocarcinomas of 131 patients and compared these findings with tumor morphology. In addition, K-ras and p53 protein expression was determined in cases where poorly differentiated adenocarcinoma was detected in the submucosa. We identified 6 patients with both intramucosal differentiated (well-to-moderately differentiated) adenocarcinoma and submucosal poorly differentiated adenocarcinoma (MwSp). The morphological tumor type was superficial in all MwSp cases. The observed MwSp adenocarcinomas had a significantly higher frequency of lymphatic invasion than the more common superficial type of adenocarcinoma. Genetic analysis of these MwSp lesions was carried out using the polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) method to detect the presence of K-ras codon 12 point mutations, and an immunologic staining technique was used to identify the presence of p53 protein overexpression. The K-ras mutation rate was 33.3%, and the p53 overexpression rate was 66.7% for the MwSp adenocarcinomas. Our findings suggest that the rapidly reduced histologic differentiation observed in some of these superficial colorectal adenocarcinomas may play a role in their higher degree of invasiveness. Received: November 17, 1999 / Accepted: July 7, 2000     

Analysis of neuroendocrine differentiation and the p53/BAX pathway in UICC stage III colorectal carcinoma identifies patients with good prognosis

Background and aims Neuroendocrine differentiation is an independent prognostic factor in colorectal cancer. Moreover, an altered p53/BAX pathway is associated with a poor clinical outcome in Union Internationale Contre le Cancer (UICC) stage III disease. Because these markers are involved in different genetic events disrupted in colorectal cancer, we investigated the prognostic power of a multimarker analysis.Patients and methods Specimens were analyzed from 59 patients with UICC stage III disease who underwent surgery for colorectal adenocarcinoma at our institution and were followed up for 5 years or until death. Tumors were studied for both p53 mutation and BAX protein expression as well as for the expression of neuroendocrine markers. Statistical analysis of each marker alone or in combination was performed.Results p53 status/BAX expression and neuroendocrine differentiation are not correlated in stage III colorectal cancers. However, the combination of both independent events identified a subgroup of patients with an excellent prognosis: Patients whose tumors were neuroendocrine marker-negative and who exhibited an intact p53/BAX pathway lived longer (mean survival, 93 months; range, 82–104 months) than patients whose tumors were either neuroendocrine marker-positive or whose tumors had a completely disrupted apoptotic pathway (41 months; range, 26–57 months; p<0.00001). In multivariate regression analysis, neuroendocrine marker-positive, p53 mutated, low-BAX-expressing tumors revealed an almost fivefold higher risk for earlier death (p<0.0001).Conclusion Disruption of the p53/BAX pathway is not pathognomonic for colorectal cancers with neuroendocrine differentiation. Both represent independent prognostic markers in UICC stage III disease. Therefore, the combined analysis of p53 status, BAX expression and neuroendocrine differentiation allows one to identify subgroups of patients with either very good or very poor prognosis.P. Grabowski and I. Sturm contributed equally to this work     

Dukes B colorectal cancer

PURPOSE: The aim of this study was to determine whether tumor location proximal or distal to the splenic flexure is associated with distinct molecular patterns and can predict clinical outcome in a homogeneous group of patients with Dukes B (T3–T4, N0, M0) colorectal cancer. It has been hypothesized that proximal and distal colorectal cancer may arise through different pathogenetic mechanisms. Althoughp53 and Ki-ras gene mutations occur frequently in distal tumors, another form of genomic instability associated with defective DNA mismatch repair has been predominantly identified in the proximal colon. To date, however, the clinical usefulness of these molecular characteristics remains unproven. METHODS: A total of 126 patients with a lymph node-negative sporadic colon or rectum adenocarcinoma were prospectively assessed with the endpoint of death by cancer. No patient received either radiotherapy or chemotherapy. p53 protein was studied by immunohistochemistry using DO-7 monoclonal antibody, andp53 and Ki-ras gene mutations were detected by single strand conformation polymorphism assay. RESULTS: During a mean follow-up of 67 months, the overall five-year survival was 70 percent. Nuclearp53 staining was found in 57 tumors (47 percent), and was more frequent in distal than in proximal tumors (55vs. 21 percent; chi-squared test,P<0.001). For the whole group, p53 protein expression correlated with poor survival in univariate and multivariate analysis (log-rank test,P=0.01; hazard ratio=2.16; 95 percent confidence interval=1.12–4.11,P=0.02). Distal colon tumors and rectal tumors exhibited similar molecular patterns and showed no difference in clinical outcome. In comparison with distal colorectal cancer, proximal tumors were found to be statistically significantly different on the following factors: mucinous content (P=0.008), degree of histologic differentiation (P=0.012), p53 protein expression, and gene mutation (P=0.001 and 0.01 respectively). Finally, patients with proximal tumors had a marginally better survival than those with distal colon or rectal cancers (log-rank test,P=0.045). CONCLUSION: In this series of Dukes B colorectal cancers, p53 protein expression was an independent factor for survival, which also correlated with tumor location. Eighty-six percent ofp53-positive tumors were located in the distal colon and rectum. Distal colon and rectum tumors had similar molecular and clinical characteristics. In contrast, proximal neoplasms seem to represent a distinct entity, with specific histopathologic characteristics, molecular patterns, and clinical outcome. Location of the neoplasm in reference to the splenic flexure should be considered before group stratification in future trials of adjuvant chemotherapy in patients with Dukes B tumors.Supported by a grant from the SICPA foundation and by the Swiss National Science FoundationRead at the meeting of The American Society of Colon and Rectal Surgeons, Boston, Massachusetts, June 24 to 29, 2000.     

Prognostic significance of the p185 protein in colorectal cancer.

The amplification and/or overexpression of the c-erbB-2/neu oncogene may play a role in tumor development and progression. The aim of this prospective study was to evaluate the prognostic value of p185 protein in colorectal cancer using immunohistochemical techniques. We analyzed 106 colorectal tumor tissue specimens from patients who had been operated on by the same surgeon and subjected to a median follow-up of 3 years. Thirty-three per cent of patients showed p185 overexpression related to an advanced stage of the disease. In patients with adenocarcinoma tumors of the colon without distant metastases, p185 detection was found to be of clinical prognostic relevance (p = 0.06).     

p53 overexpression and K-ras gene mutations in primary sclerosing cholangitis-associated biliary tract cancer

Cholangiocarcinoma occurs frequently in patients with primary sclerosing cholangitis (PSC). We evaluated the incidence and prognostic significance of p53 protein overexpression and K-ras gene mutations in patients with biliary tract cancer and PSC. p53 protein expression was determined in specimens from 12 patients with biliary tract cancer, using the antibody, D07. K-ras mutations were detected using DNA sequencing and a mutation ligation assay. Accumulation of p53 protein was detected in 6 of 12 tumors (50%). K-ras mutations were detected in 4 of 12 tumors (33%). Overall survival in patients with p53-negative tumors was significantly longer (P < 0.05) than that in patients with p53-positive (mutant) tumors. Similarly, overall survival was significantly longer (P < 0.05) in the absence of a K-ras mutation than in patients with a tumor containing a K-ras mutation. Mean interval from the time of diagnosis of PSC until the diagnosis of biliary tract cancer was significantly shorter (P < 0.05) in patients with p53 overexpression than in those patients without p53 overexpression (2 versus 47 months). p53 overexpression and K-ras mutations occur commonly in patients with PSC and biliary tract cancer and are associated with a shortened survival. Patients with longstanding PSC are less likely to have these genetic alterations and may have a better prognosis.     

Serum p53 antibody assay: evaluation in colorectal cancer

INTRODUCTION: Alterations of the tumor suppressor gene p53 and its protein synthesis is the most commonly observed genetic feature in human cancers. Direct diagnosis of the gene mutation using sequencing is the gold standard method. However, it requires advanced technology and is only performed in specialized research units. CURRENT KNOWLEDGE AND KEY POINTS: Demonstration of intratumoral p53 protein accumulation using immunohistochemistry is a routine diagnostic technique. Serum detection of p53 antibodies using ELISA has been recently developed. It is an easily feasible and reproducible method for the diagnosis of p53 alterations due to self-immunization in some patients in response to intratumoral p53 protein overexpression. This phenomenon is inconstant (about one-third of the patients with a p53 gene mutation produce antibodies) and its mechanism is unclear. p53 Antibodies are found in 25% of the patients with colorectal cancer, independently of traditional tumor markers (carcinoembryonic antigen and carbohydrate antigen 19.9). The presence of these antibodies is not linked to the tumor stage. Since their ratios vary during the treatment, they might constitute a new tumor marker. FUTURE PROSPECTS AND PROJECTS: Early appearance of p53 serum antibodies during tumor development should make them useful for the detection of malignant transformation in patients with preneoplastic disease such as ulcerous colititis. Whether the presence of p53 antibodies in colorectal cancer patients has a prognostic significance requires further assessment.     

Prognostic significance of microsatellite instability in sporadic colorectal cancer

Background and aims Colorectal cancers exhibiting microsatellite instability (MSI) appear to have unique biological behavior. The influence of MSI on the prognosis of sporadic colorectal cancers is controversial and requires further investigation. The aim of this study was to analyze the association between MSI status and clinicopathological features and prognosis in sporadic colorectal cancer patients.Patients and methods Of the 322 consecutive colorectal cancer patients operated upon at the Seoul National University Hospital between January and December 1998, we examined the clinicopathological features and prognosis of 248 patients with sporadic primary colorectal cancer. The MSI status of these 248 patients has been reported in a previous study. Of the 248 patients, 23 (9.3%) had MSI+ tumors. The patients clinicopathological parameters were obtained from their medical records, and follow-up and survival data were obtained from medical records and phone calls.Results MSI+ sporadic colorectal cancers were found predominantly in the proximal colon (p<0.001) and were associated with poor differentiation (p=0.030), a lower preoperative serum carcinoembryonic antigen (CEA) level (p=0.012), and less frequent systemic metastasis (p=0.034) than MSI– tumors. Low tumor grade (p=0.022), low tumor T-stage (p=0.002), no lymph node metastasis (p<0.001), no systemic metastasis (p<0.001), adjuvant chemotherapy (p<0.001) and MSI+ status (p=0.038) were independent favorable prognostic factors for survival in sporadic colorectal cancer patients.Conclusion MSI status was an independent favorable prognostic factor for survival in sporadic primary colorectal cancer patients.     

Prognostic value of cyclin D1 overexpression in correlation with pRb and p53 status in non-small cell lung cancer (NSCLC)

Purpose: The aim of this study was to assess the impact of cyclin D1 overexpression (considered separately or jointly with previously assessed p53 and pRb statuses) on survival in a group of 111 surgically treated non-small cell lung cancer patients (NSCLC). Methods: Cyclin D1 accumulation was assessed immunohistochemically, with the use of monoclonal antibody (DCS-6, DakoCytomation) and the alkaline phosphatase–anti-alkaline phosphatase (APAAP) technique. Results: Overexpression of cyclin D1 was found in 55 samples (49%), whereas the altered phenotypes cyclin D1+/p53+ or cyclin D1+/pRb– were found in 23 (22%) and 9 samples (9%), respectively. Statistical analysis was performed for different cut-off values and the only significant differences were found if samples with some expression of each protein were considered positive. There was no relationship between cyclin D1 overexpression and major clinicopathological factors, including p53 expression; however, there was a direct correlation between cyclin D1 and pRb protein expression (p=0.007). Cyclin D1 accumulation did not influence patients survival. Of all possible cyclin D1/p53, cyclin D1/pRb and cyclin D1/p53/pRb phenotypes, patients with cyclin D1–/p53+ phenotype had shortened overall survival compared to other patients (p=0.027, HR=1.8). In the multivariate analysis, the only variable associated with shortened overall and disease-free survival was the stage of disease (p<0.001). Conclusions: These results suggest the lack of prognostic value of cyclin D1 overexpression in NSCLC patients.     

Influence of thymidylate synthase and p53 protein expression on clinical outcome in patients with colorectal cancer

Aims Thymidylate synthase (TS) and tumor suppressor p53 are two proteins with an influence on tumor resistance to radio-chemotherapy that is well known. For this reason we tested the effect of TS and p53 expression on clinical outcome (tumor recurrence and survival) in patients after curative tumor resection, especially in patients who received adjuvant radio-chemotherapy.Patients and methods A total of 120 patients with colorectal cancer were included in the study. A curative resection was possible in 83 patients, and 30 of this group received adjuvant therapy. For the immunohistochemical staining of tumor specimens, monoclonal antibody (mAb) TS 106 against TS and mAb DO-1 against p53 protein were used. TS positivity was defined as a moderate to high staining intensity in the cytoplasma of cells and p53 positivity as nuclear staining of tumor cells in >10% of these cells.Results Thymidylate synthase immunoreactivity was found in 59% of all cases and p53 staining in 51%. No relation between clinicopathological features and p53 expression was found in contrast to TS expression, where a highly significant association of TS-positive cases with tumor invasion (pT) was observed. Curatively resected patients with a TS-positive tumor developed tumor recurrence/distant metastases significantly more often than TS negative tumors. The same result was found when comparing p53-positive with p53-negative tumors and TS+/p53+ with TS–/p53– tumors. TS expression was highly significantly associated with poor survival and was the strongest independent prognostic factor in multivariate analysis, followed by lymph node status.Conclusion Thymidylate synthase expression seems to be an independent prognostic factor and a possible predictor of tumor recurrence in patients with colorectal cancer.     

p53 protein expression in resected invasive esophageal cancer

Many studies have reported the increased expression of p53 protein in various human malignancies and its accumulation have been considered an intermediate biomarker in multistage carcinogenesis. This study was designed to evaluate p53 expression by immunohistochemistry using Dako p53, D0-7 monoclonal antibody in 33 resected invasive squamous cell esophageal cancers (SqCC). The relationship between p53 immunoreactivity and clinicopathologic parameters was determined by the Chi-square test and Student's t test. p53 protein overexpression (more then 10% positive staining cancer cells) was found in 15 out of 33 (45%) tumors. Positive test was found in 38% cases in Stage IIA, 57% in Stage IIB, 45% in Stage III and 50% cases in Stage IV. p53 overexpression was observed in 48% of tumors with lymph nodes metastases, and 41% of tumors without lymph nodes metastases. In respect of tumor differentiation, cases graded as G1, G2 and G3 were positive in 50%, 50% and 40%, respectively. Thirteen per cent of patients with p53 protein overexpression and 16% of patients without p53 protein overexpression survived more than 3 years. There was no correlation between p53 overexpression and stage, tumor differentiation, lymph nodes metastases, and patients survival. In conclusion our results showed that p53 overexpression did not correlate with clinicopathologic feature of invasive SqCC of the esophagus and p53 protein overexpression was unsuitable for predicting the outcome of patients after surgical resection.     

Mutations in APC,Kirsten-ras,and p53--alternative genetic pathways to colorectal cancer

Colorectal cancer is one of the most significant causes of cancer death. A genetic model for colorectal cancer has been proposed in which the sequential accumulation of mutations in specific genes, including adenomatous polyposis coli (APC), Kirsten-ras (K-ras), and p53, drives the transition from healthy colonic epithelia through increasingly dysplastic adenoma to colorectal cancer. We have characterized tumor mutation spectra in a large cohort of colorectal cancer patients. In marked contrast to the predictions of the sequential model of mutation accumulation, only 6.6% of tumors were found to contain mutations in APC, K-ras, and p53, with 38.7% of tumors containing mutations in only one of these genes. The most common combination of mutations was p53 and APC (27.1%), whereas mutations in both p53 and K-ras were extremely rare. Statistical analysis (two-sided Fisher's exact test) confirmed that mutations in K-ras and p53 co-occurred less frequently than expected by chance (P < 0.01, Fisher's exact test). This finding suggests that these mutations lie on alternate pathways of colorectal tumor development. The heterogeneous pattern of tumor mutations in our patient cohort suggests that multiple alternative genetic pathways to colorectal cancer exist and that the widely accepted genetic model of cancer development is not representative of the majority of colorectal tumors.     

Thymidine phosphorylase, dihydropyrimidine dehydrogenase and thymidylate synthase mRNA expression in primary colorectal tumors—correlation to tumor histopathology and clinical follow-up

Aim Evaluation of thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), and thymidylate synthase (TS) mRNA levels in formalin-fixed, and paraffin-embedded tissues of patients with colorectal cancer and their prognostic and/or predictive value.Materials and methods Total RNA was isolated from microdissected, formalin-fixed, and paraffin-embedded tissues (controls and tumor) and subjected to quantitative RT-PCR (QRT-PCR) in the LightCycler system. Resulting mRNA levels correlated to tumor histology (n=102) and the clinical follow-up in patients treated by resection alone (n=40) and by resection plus adjuvant 5-FU-based chemotherapy (n=52).Results Correlation to histopathological parameters revealed a significant association between tumor stage and the TP mRNA level (T and N category and UICC) as well as the TP:DPD (T and N category and UICC) and TS:DPD (T category) ratio. In addition, tumor differentiation was correlated to the TS mRNA level and the TS:DPD ratio. Finally, the TS:DPD ratio was a prognostic marker for overall survival in patients receiving resection alone (p=0.032). Moreover, a high TP:DPD ratio (>8.1; p=0.002) and, marginally, low DPD (<8.2; p=0.05) mRNA levels significantly correlated to disease-free survival.Conclusion We present a novel, standardized approach for TP, DPD, and TS mRNA quantification in archival tissue specimens and applied this to a large series of primary colorectal tumors. Correlations to histopathological parameters and clinical follow-up revealed an association of TP, DPD and TS mRNA expression patterns with tumor stage and suggested new prognostic and predictive markers for patients with colorectal cancer.