Site impact on colorectal cancer biological behavior in terms of clinicopathological and molecular features.

PURPOSE: We investigated the biological behavior of proximal and distal colorectal adenocarcinomas (CRC), intending to determine specific segmental differences, possibly arising from the distinct genetic pathways involved in their development. METHODS: Thirty-six proximal and 83 distal cancers were comparatively and retrospectively analyzed, regarding tumor stage, grade and Ki-67, p53 and Bcl-2 immunohistochemical expression. RESULTS: Proximal tumors were more likely to be poorly differentiated (p=0.005) and to exhibit low Ki-67 and p53 expression (<20% and ≤ 30% stained nuclei respectively; p=0.026 and 0.0014, respectively). Distal lesions were more likely to be moderately differentiated (p=0.001), to display moderate Ki-67 expression (20-50% stained nuclei, p= 0.013) and p53 staining higher than 30% stained nuclei (p= 0.0014). Such segmental variations regarding mainly p53 and to a lesser extent Ki-67 were seen within most of the specific sub-groups of patients (stratified by stage, grade, gender and age). An association between Bcl-2 expression and distal site was also observed among females (p=0.008). CONCLUSION: Proximal and distal cancers displayed different clinicopathological and molecular patterns, reinforcing the proposal that they are genetically and biologically different entities. Potential clinical applications of these findings should be investigated.

Immunohistochemical expression of bcl-2 in UICC stage I and III colorectal carcinoma patients: correlation with c-erbB-2, p53, ki-67, CD44, laminin and collagen IV in evaluating prognostic significance.

BACKGROUND: The objective of this study was to evaluate the expression of bcl-2 in UICC stage I and stage III (Dukes's stage B and C) colorectal adenocarcinoma and to examine its association with clinicopathological features, c-erbB-2, p53, ki-67, CD44, laminin and collagen IV and long term outcome. METHODS: Paraffin embedded specimens from 61 patients with UICC stage I (Dukes's stage B) and 39 patients with UICC stage III (Dukes's stage C) colorectal adenocarcinoma who were treated with surgery were assessed. We determined by immunohistochemistry the expression of bcl-2, c-erB-2, p53, ki-67, CD44, laminin and collagen IV with 5 year follow up. RESULTS: Cytoplasmic staining of the bcl-2 gene product was seen in the tumour cells of 27 cases (27%). Expression of bcl-2 protein was unrelated to patient sex, age, tumour site or tumour grade, but was related to tumour stage (p = 0.012). No significant association was demonstrated between bcl-2 and c-erbB-2, p53 or CD44. However, there was very strong evidence of correlation between bcl-2 staining and ki-67, laminin and collagen IV. There was a trend towards increased survival in patients whose tumours expressed bcl-2 protein. When a correlation between bcl-2 and the other markers had been made the positive expression of bcl-2 was beneficial. CONCLUSIONS: The results from this study would suggest that expression of bcl-2 appear to be useful in selecting a group of colorectal cancer patients with a better prognosis.

Colorectal adenomas with a low frequency of ki-ras mutations: a sample from a population with a low mortality rate from colorectal cancer.

OBJECTIVE: To detect and analyse ki-ras point mutations in colorectal adenomas and carcinomas in patients from Greece, where mortality rate from colorectal cancer is lower than that in other European countries and the USA. PATIENTS AND METHODS: As a method we used PCR-RFLP technique, to examine ki-ras codons 12 and 13 mutations in 450 paraffin embedded tissues, consisting of 141 normal mucosas, 165 adenomas and 144 sporadic colorectal cancers taken from 141 patients. RESULTS: Frequency of ki-ras mutations was 3.2% (3/93) in small adenomas, 5.2% (3/57) in greater than 1 cm adenomas, 20% (3/15) in tissues where adenoma and cancer coexisted and 39.5% (57/144) in colorectal cancer. CONCLUSION: These data showed that the frequency of ki-ras mutations was low in all sizes of polyps and high in carcinomas in a sample of a population, characterized by a low mortality rate from colorectal cancer. Ki-ras mutations were not an early event of colon carcinogenesis in these patients and the low frequency of ki-ras mutations in adenomas may probably have some relevance to the low mortality rate. Our findings could be explained, not by the dietary habits of this population, but by the presence of other hitherto unknown environmental factors.

Prognostic evaluation of CD44 expression in correlation with bcl-2 and p53 in colorectal cancer.

To investigate the expression of CD44 in colorectal cancer and examine its association with clinicopathological features, bcl-2, p53 and long-term outcome, paraffin-embedded tumour specimens from 61 patients with Dukes stage B (AJCC/UICC stage I) and 39 patients with Dukes stage C (AJCC/UICC stage III) colorectal adenocarcinoma were assessed by immunohistochemistry. The expression of CD44, bcl-2 and p53 were correlated with 5-year follow-up. Low CD44 expression was present in 30%, moderate in 30% and extensive in 40% of cases. It was not related to patient sex and age but was related to tumour differentiation, stage and tumour site. No association was demonstrated between CD44 and bcl-2. However, there was significant evidence of an association between CD44 and p53 in 66 cases in which p53 was previously assessed. There was a trend towards increased survival in patients whose tumours expressed lower levels of CD44 protein. When entered into multivariate analysis model, which also included bcl-2 and p53, CD44 staining emerged as an indicator of poor prognosis in colorectal cancer patients.

p53 protein accumulation and colonic adenoma recurrence.

OBJECTIVES: The prognostic value of p53 protein accumulation in colonic adenomas is still controversial. The aim of the present study was to determine whether the evaluation of p53 protein accumulation in newly diagnosed colonic adenomas could predict the development of metachronous adenomas. DESIGN/METHODS: Fifty-five patients who underwent prior endoscopic polypectomy for colonic adenomas were colonoscopically re-evaluated at 24-38 months after index colonoscopy. In cases with more than one adenoma, the one with the greatest diameter and the most serious histology was taken into account. p53 protein expression was immunohistochemically examined using specific monoclonal antibody. RESULTS: p53 protein was detected in 41.8% of the 55 index adenomas. Recurrent adenomas were present in 21 patients (38.2%). Metachronous adenomas were present in 56.5% of patients with p53-positive index adenomas and in 25% of those with p53-negative index adenomas (odds ratio 3.90, P = 0.018). Among patients with 1 or 2 index adenomas, metachronous adenomas were found in 50% of those with p53-positive index adenomas and in 22.6% of those with p53-negative index adenomas (odds ratio 3.43, P= 0.042). Multivariate stepwise logistic regression analysis revealed that number of index adenomas per patient (1 or 2 versus > 2) and p53 expression (positive versus negative) in index adenomas contain independent prognostic information for adenoma recurrence (chi2 = 8.2, P= 0.004 and chi2 = 4.08, P = 0.04 respectively). Patients aged < 60 years developed recurrent adenomas relatively more frequently if they had a p53-positive index adenoma (P= 0.068). In the subgroup of patients aged < 60 years with 1 or 2 index adenomas, the recurrence of adenomas was more frequent in those with a p53-positive index adenoma but the difference did not reach statistical significance (P= 0.13). CONCLUSIONS: Our data suggest that p53 expression in index adenomas is associated with recurrent colonic adenomas.

Proliferative patterns of rectal mucosa as predictors of advanced colonic neoplasms in routinely processed rectal biopsies.

OBJECTIVES: We sought to determine whether the evaluation of rectal cell proliferation in routinely processed rectal biopsies of apparently normal mucosa can predict the presence of advanced colonic neoplasms. METHODS: Fifty consecutive patients, who did not meet any of the following exclusion criteria, underwent total colonoscopy. Patients with nonadvanced adenomas, inflammatory bowel disease, hereditary predisposition to colonic cancer, or a history of colonic neoplasms were excluded. Patients with neoplasms in the distal 40 cm of the large bowel were also excluded. An adenoma was considered advanced if it had a diameter > 1 cm, or villous or severe dysplasia histology were present. In 26 of the 50 patients (Group A: 16 men, 10 women; mean age, 65 yr) advanced colonic neoplasms (advanced adenomas or cancer) were detected; in the remaining 24 (Group B: 13 men, 11 women; mean age, 66 yr) the large bowel was free of neoplasms. In all patients the proliferative patterns of apparently normal rectal mucosa were evaluated using the monoclonal antibody MIB-1 to assess the expression of Ki-67 antigen in routinely processed tissues. Proliferation index for the entire crypt, as well as proliferation indices for each of the five equal compartments, into which the crypt had been divided longitudinally, were calculated for each patient. RESULTS: The mean proliferation indices were similar between the two groups compared. The mean proliferation index for the upper crypt compartments (4 + 5) in the Group A patients was significantly higher than for those of the Group B patients (p < 0.01). Multivariate stepwise logistic regression analysis revealed that among gender, age, and proliferative parameters, the pattern of cell proliferation in the upper rectal crypt (4 + 5) compartment was the only predictor of advanced colonic neoplasms (beta = 11.01, p < 0.001). CONCLUSIONS: Our data suggest that the evaluation of the upward expansion of the rectal crypt proliferative zone in routinely processed rectal biopsies of apparently normal mucosa appears to predict the presence of advanced colonic neoplasms. These preliminary results should be confirmed in larger studies.

p53 and bcl-2 protein expression in rectosigmoid adenomas.

OBJECTIVE: The aim of this study was to evaluate whether p53 or bcl-2 protein expression in rectosigmoid adenomas is associated with histological characteristics of the adenomas and with presence of synchronous advanced proximal neoplasms. METHODS: Seventy-six average-risk patients who underwent total colonoscopy and had rectosigmoid adenoma(s) were studied. An adenoma was considered advanced if villous histology and/or severe dysplasia and/or diameter > 1 cm were present. p53 and bcl-2 protein expression was immunohistochemically examined using specific monoclonal antibodies. RESULTS: p53 protein was detected in 43% and bcl-2 in 93% of the 76 rectosigmoid adenomas. Advanced compared with nonadvanced adenomas were significantly more frequently p53-positive (28 of 44 or 63.6% vs five of 32 or 15.6%, p < 10(-4)) or had a bcl-2 score of 12 (20 of 44 or 45.5% vs five of 32 or 15.6%, p = 0.007). Proximal advanced neoplasms were mainly found in patients with rectosigmoid adenomas positive for p53 and with a bcl-2 score of 12 (six of 17 or 35.3% vs 2/59 or 3.4%, OR: 15.6, p = 0.001) and in particular in those with advanced rectosigmoid adenomas positive for p53 and with a bcl-2 score of 12 (six of 13 or 46.2% vs two of 31 or 6.5%, OR: 12.4, p = 0.007). CONCLUSION: p53 expression and bcl-2 protein overexpression in rectosigmoid adenomas are associated with advanced histology and a high risk of synchronous advanced proximal colon neoplasm.

Predictors of the early development of advanced metachronous colon adenomas.

BACKGROUND/AIMS: In order to reduce the number of colonoscopies performed for the surveillance of patients after polypectomy, suitable predictors of adenomas recurrence are needed. The aim of this study was to find predictors of the early development of metachronous adenomas and specifically of advanced ones. MATERIALS AND METHODS: Forty-four patients underwent total colonoscopy 24-26 months after initial endoscopic polypectomy. All polyps were endoscopically removed and an adenoma was considered as advanced if the diameter was > 1 cm and/or villous component and/or severe dysplasia were present. RESULTS: Metachronous adenomas were detected in 16 (36.4% patients. Five (11.4%) of them had advanced metachronous adenomas. Early recurrence of adenomas was significantly correlated with the total number of indices adenomas (p = 0.027). On the contrary, the presence of metachronous adenomas was not related to any of the patients' characteristics nor to the site and the histology of the indices adenomas. The development of advanced metachronous adenomas during the same period was significantly correlated with patients' age, as it was observed only in patients aged > or = 60 years (5/21 or 23.8%) and in none of the patients aged < 60 years (Odds ratio: 15.7, p = 0.02). Logistic regression analysis revealed that patient's age was the only significant predictor of the early development of advanced metachronous adenomas (beta = 0.40, p = 0.02) and that the number of the indices adenomas was the only significant predictor for the recurrence of all adenomas (beta = 1.59, p = 0.02). CONCLUSIONS: 1. Only patients aged > or = 60 years seem to develop advanced metachronous adenomas two years after polypectomy and 2. The likelihood for developing metachronous adenomas during the same period is related to the number of indices adenomas.

Proliferative activity in colonic adenomas as a predictor of metachronous adenomas as assessed by proliferating cell nuclear antigen immunohistochemistry.

OBJECTIVES: The aim of this study was to determine whether cell proliferation in colonic adenomas, as estimated by proliferating cell nuclear antigen (PCNA), predicts the development of metachronous colonic adenomas. METHODS: Forty patients who underwent prior endoscopic polypectomy for colonic adenomas were reevaluated by colonoscopy 2 yr later. The expression of PCNA was studied in all adenomas that were removed. A five-point semiquantitative scale of 1-5 was used to estimate the PCNA score by the percentage of positively stained cells. RESULTS: Among the 40 patients studied, 16 developed recurrent adenomas (group A) and 24 were free of adenomas (group B). At initial colonoscopy, a total number of 51 adenomas (25 in group A and 26 in group B), were found. The median PCNA score in group A and group B index adenomas was 4 (interquartile range, 3-5) and 2 (interquartile range, 1-3), respectively (p < 0.01, Mann-Whitney U-test). A stepwise logistic regression analysis showed that PCNA score is a significant risk factor (p = 0.007, odds ratio 15.8, 95% confidence interval 2.2-112.4) in predicting adenoma recurrence. The median PCNA score in metachronous adenomas was 2 (interquartile range, 1-3). The difference in the PCNA score between group A index and metachronous adenomas was again statistically significant (p < 0.01, Mann-Whitney U-test). CONCLUSIONS: We conclude that the increased expression of PCNA in colonic adenomas may be a predictor for metachronous adenomas.