Flow cytometric DNA ploidy and S-phase fraction correlate with histopathologic indicators of tumor behavior in colorectal carcinoma

Prognostic Significance of DNA Aneuploidy and p21ras Oncoprotein Expression in Colorectal Cancer and Their Role in the Determination of Treatment Modalities

The purpose of the present study was to investigate the prognostic significance of DNA ploidy, S-phase fraction and p21ras oncoprotein expression in patients with colorectal cancer and to correlate these factors with the clinical behavior of the tumors and their response to therapy. Of 79 patients with colorectal cancer 57% (45/79) had early stage disease. Forty-one percent (32/79) had aneuploid tumors while 30% (24/79) of the tumors had a high (>10%) S-phase fraction. p21ras oncoprotein expression was detected in 38% (30/79) of tumors. Patients with aneuploid tumors had a worse prognosis than patients with diploid tumors (p=0.0002). Similarly, patients with high S-phase fraction tumors had a shorter survival than those with low S-phase fraction tumors (p=0.005). No such difference was found between p21ras-positive and p21ras-negative tumor subgroups. In early stage colorectal cancer, aneuploidy was closely correlated with disease outcome (p=0.029). Early stage patients with diploid tumors who received radiotherapy and chemotherapy had a better prognosis than patients with aneuploid tumors. In conclusion, DNA ploidy is a significant and independent prognostic factor in colorectal cancer. Aneuploidy and genetic alteration of the p21ras oncoprotein are important in determining the biological aggressiveness of colorectal cancer. Furthermore, DNA ploidy may identify those subgroups of patients with early stage disease who may benefit from more aggressive treatment.

Pancreatitis-associated protein is related closely to neoplastic proliferative activity in patients with colorectal carcinoma

Pancreatitis-associated protein (PAP) is a secretory protein that is not only expressed during acute pancreatitis but also in pancreatic adenocarcinoma, gastric carcinoma, hepatocellular carcinoma, and colorectal carcinoma. Expression in carcinoma might be another characteristic of PAP. The aim of our study was to assess, in 27 patients undergoing surgery for colorectal carcinoma, the expression of the PAP mRNA and to evaluate its association with DNA ploidy and proliferative activity (S-phase fraction, SPF) by reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometric analysis (FCM). PAP mRNA was expressed in 29.6% (8 of 27) of the patients with colorectal carcinoma. DNA aneuploid and high SPF were found in 87.5% (7 of 8) of patients with PAP mRNA positive colorectal carcinoma. The serum PAP level was significantly elevated in patients with colorectal carcinoma when compared with the healthy subjects. Twelve of the 27 patients with colorectal carcinoma had high serum PAP concentrations (>25 ng/mL) and the mean SPF was 17.82% +/- 8.02%, which was significantly higher compared with the normal colorectal tissue group (7.33% +/- 3.18%, P < 0.05). The mean serum PAP concentration of DNA aneuploidy colorectal carcinomas was 46.67 +/- 17.58 ng/mL, which was significantly different when compared with the DNA diploidy group (19.18 +/- 8.89 ng/mL, P < 0.05). PAP mRNA expression and serum PAP levels are closely related to neoplastic proliferative activity in patients with colorectal carcinoma. No significant differences are observed between PAP mRNA expression and clinicopathologic parameters (P > 0.05).

Immunohistochemical estimation of cell cycle phase in laryngeal neoplasia

We previously developed an immunohistochemical method for estimating cell cycle state and phase in tissue samples, including biopsies that are too small for flow cytometry. We have used our technique to examine whether primary abnormalities of the cell cycle exist in laryngeal neoplasia. Antibodies against the markers of cell cycle entry, minichromosome maintenance protein-2 (Mcm-2) and Ki67, and putative markers of cell cycle phase, cyclin D1 (G1-phase), cyclin A (S-phase), cyclin B1 (G2-phase) and phosphohistone H3 (Mitosis) were applied to paraffin-embedded sections of normal larynx (n=8), laryngeal dysplasia (n=10) and laryngeal squamous cell carcinoma (n=10). Cells expressing each marker were determined as a percentage of total cells, termed the labelling index (LI), and as a percentage of Mcm-2-positive cells, termed the labelling fraction (LF). The frequency of coexpression of each putative phase marker was investigated by confocal microscopy. There was a correlation between Mcm-2 and Ki67 LIs (ρ=0.93) but Mcm-2 LIs were consistently higher. All cells expressing a phase marker coexpressed Mcm-2, whereas Ki67 was not expressed in a proportion of these cells. The putative phase markers showed little coexpression. Labelling index values increased on progression from normal larynx through laryngeal dysplasia to squamous cell carcinoma for Mcm-2 (P=0.001), Ki67 (P=0.0002), cyclin D1 (P=0.015), cyclin A (P=0.0001) and cyclin B1 (P=0.0004). There was no evidence of an increase in the LF for any phase marker. Immunohistochemistry can be used to estimate cell cycle state and phase in laryngeal biopsies. Our data argues against primary cell cycle phase abnormalities in laryngeal neoplasia.

Loss of heterozygosity and DNA aneuploidy in colorectal adenocarcinoma

BACKGROUND

This study evaluated the relationship between DNA aneuploidy and loss of heterozygosity (LOH) at different genetic loci in colorectal adenocarcinoma.

METHODS

A total of 112 patients with surgically removed colorectal adenocarcinoma in Taipei Veterans General Hospital from January 1999 to July 2001 were included in this study. The pattern of DNA ploidy was determined with DNA flow cytometry, and the LOH of various genetic loci was determined with fluorescence polymerase chain reaction and denaturing gradient gel electrophoresis. The relationship between DNA ploidy, LOH of various genetic loci, and clinicopathologic variables was analyzed with the chi(2) test with Yates' correction as well as by multivariate binary logistic regression analysis.

RESULTS

Seventy-one (63.4%) of the 112 carcinomas had DNA aneuploidy. The DNA aneuploidy was not associated with any clinicopathologic variable. Ninety-one tumors (81.3%) exhibited LOH in at least one genetic locus. In the univariate analysis, the DNA aneuploidy was associated with LOH of Tp53-penta, D8S254, D5S346, and high-frequency LOH (P =.001, P =.016, P =.041, and P <.001, respectively). In the multivariate analysis, the most significant factor influencing DNA aneuploidy was D8S254, followed by Tp53-penta, high-frequency LOH, and D5S346.

CONCLUSIONS

DNA aneuploidy is strongly associated with LOH at specific genetic loci.

A novel immunohistochemical method to estimate cell-cycle phase distribution in archival tissue: implications for the prediction of outcome in colorectal cancer

An immunohistochemical method for assessing cell-cycle phase distribution in colorectal resection specimens would enable phase data to be incorporated into diagnostic algorithms for the estimation of prognosis and response to adjuvant chemotherapy in colorectal cancer. In contrast to flow cytometry, an immunohistochemical method would also allow the phase distribution to be examined within morphologically heterogeneous regions of neoplasms. Paraffin sections of normal colon (n = 25), colonic adenoma (n = 15), and colonic adenocarcinoma (n = 30) were analysed by immunohistochemistry using antibodies against markers of cell-cycle entry, Mcm-2 and Ki67, and putative markers of the cell-cycle phase, cyclins D1 and E (putative markers of G1 phase), cyclin A (S phase), cytoplasmic cyclin B1 (G2 phase), and phosphohistone H3 (M phase). The phase specificity of each marker was assessed by examining the degree of co-expression of adjacent phase markers using double-antibody fluorescence confocal microscopy and by comparison with flow cytometric analysis performed on adjacent tissue sections. The S-phase specificity of detectable cyclin A was also assessed in combination with in situ DNA replication using fluorescence confocal microscopy. All cells expressing phase markers co-expressed Mcm-2. Adjacent phase markers were not significantly co-expressed, confirming the relative specificity of these markers in tissue sections of colon. Cell-cycle phase distribution, calculated by immunohistochemistry, compared well with phase analyses obtained by flow cytometry. No cells expressed cyclin A in the absence of active DNA replication. The S-phase labelling index, as defined by detectable cyclin A expression, showed a positive correlation with the Mcm-2 labelling index and increased in the progression from normal colon to adenocarcinoma. In conclusion, a combination of these cell-cycle phase markers can be used to calculate the distribution of cells throughout each phase of the cell cycle in colorectal tissue sections. Detectable cyclin A can be used as a surrogate marker of S phase and may be of value in predicting prognosis and response to adjuvant therapy.

DNA index and S-phase fraction in curative resection of colorectal adenocarcinoma: analysis of prognosis and current trends

The DNA index (DI) and S-phase fraction (SPF) have been said to be independent factors in colorectal adenocarcinoma and have a different distribution from the clinicohistologic parameters. This study assesses the real efficacy of DI and SPF for curative resection of colorectal adenocarcinomas with respect to the prognosis and the clinicohistologic parameters. From July 1991 to October 1994 a total of 666 patients underwent curative resection of colorectal adenocarcinoma and DNA flow cytometry in Kaohsiung Chang Gung Memorial Medical Center Hospital, Taiwan. We defined diploid tumors as having a DI of ? 0.9 but <1.1 and a nondiploid tumor as having a DI of <0.9 OR > 1.1. A high SPF was defined as being more than the median value for the total SPF. Altogether, 495 cases (74.32%) had a 5-year cancer-free survival. Tumor stage, DI, tumor location, and tumor morphology were associated with significant cancer-free survival in the univariate analysis (p = 0.0295, <0.001, 0.0357, and <0.001, respectively). After all factors were entered into the multivariate analysis, the independent factors for cancer-free survival were found to be stage, tumor location, and morphology (p < 0.001, 0.012, and 0.044, respectively). In cases distinguished by the DI, diploid tumors had significantly more frequent right colon locations (p <0.001). After cases were separated by the SPF (median value 18.4%), better histology (well differentiated adenocarcinoma) was noted with a low SPF (p = 0.017). No other clinicohistologic parameters had significant differences shown by the DI or SPF. Thus DI and SPF failed to appear as independent factors for 5-year cancer-free survival. The independent factors for curative colorectal adenocarcinoma were tumor stage, location, and morphology. Diploid tumors were located at the right colon more often, and low SPF indicated better histology in the univariate analysis.

The use of flow cytometry in assessing malignancy in bone and soft tissue tumors

Since 1982, the orthopaedic research laboratories at the authors' hospital has done flow cytometric and more recently cytofluorometric deoxyribonucleic ploidic analyses of samples of bone and soft tissue tumors. The current authors attempt to define the value of such studies in distinguishing benign from malignant tumors, in conforming to stage of the tumors, and in helping to predict metastasis and death. The series consists of 1134 patients in whom the disease was verified and the survival data were available as a result of a questionnaire study. Statistically, the ploidic analyses were of remarkable value in defining malignancy and in correlating with the stage of the lesion. They were of less value in predicting survival, particularly for patients with osteosarcoma and chondrosarcoma, but seemed to predict survival effectively for patients with soft tissue sarcomas.

c-Myb and Bcl-x overexpression predicts poor prognosis in colorectal cancer: clinical and experimental findings

The aim of this study was twofold: to assess the relationship between c-Myb and Bcl-x expression and to evaluate the prognostic significance of their expression in colorectal carcinoma (CRC) patients. Analysis of tumors from 91 CRC patients for expression of c-Myb and Bcl-x revealed a significant relationship between these two proteins. Kaplan-Meier's analysis showed an increased risk of relapse and death in patients whose tumor specimens displayed high c-Myb levels and Bcl-x positivity. Similar results were also observed excluding Dukes' D patients. Molecular analysis using three c-Myb-overexpressing LoVo clones indicated that c-Myb overexpression was accompanied by up-regulation of Bcl-x(L) protein and mRNA. Tumors originating from these clones injected in nude mice were significantly larger than those formed in mice injected with parental or vector-transfected LoVo cells. Moreover, tumors derived from parental and control vector-transfected but not from c-Myb-overexpressing LoVo cells showed high frequency of apoptotic cells. These results provide direct evidence of an association between c-Myb and Bcl-x expression and suggest that expression of both molecules might be a useful prognostic marker in CRC.

Evaluation of multiple bio-pathological factors in colorectal adenocarcinomas: independent prognostic role of p53 and bcl-2

About 40% of patients with colorectal carcinoma will develop local or distant tumour recurrences. Integrated analyses of bio-pathological markers, predictive of tumour aggressiveness, may offer a more rational approach to planning adjuvant therapy. To this end, we analysed the correlation between p53 accumulation, Bcl-2 expression, DNA ploidy, cell proliferation and conventional clinico-pathological parameters by testing the prognostic significance of these variables in a series of 171 colorectal carcinoma patients with long-term follow-up. The relationships among the various bio-pathological parameters, analysed by multiple correspondence analysis, showed 2 different clinico-biological profiles. The first, characterised by p53 negativity, Bcl-2 positivity, diploidy, low percentage of cells in S-phase (%S-phase), a low Ki-67 score, is associated with Dukes' A-B stage, well differentiated tumours and lack of relapse. The second, defined by p53 positivity, Bcl-2 negativity, aneuploidy, high %S-phase and elevated Ki-67 score, correlates with Dukes' C-D stage, poorly differentiated tumours and presence of relapse. When these parameters were examined according to Kaplan-Meier's method, significantly shorter disease-free (DFS) and overall survival (OS) were also observed in patients bearing p53 positive and Bcl-2 negative tumours, in Dukes' B stage. In multivariate analysis, p53 accumulation and Bcl-2 expression emerged as independent predictors of a worse and better clinical outcome, respectively. Our results indicate that, in colorectal adenocarcinomas, a biological profile, based on the combined evaluation of p53 and Bcl-2, may be useful for identifying high risk patients to be enrolled in an adjuvant setting, mainly in an early stage of the disease. Int. J. Cancer (Pred. Oncol.) 84:545-552, 1999.

Prognostic significance of DNA ploidy, S-phase fraction, and P-glycoprotein expression in colorectal cancer

BACKGROUND AND OBJECTIVES

Parameters that allow prediction of the disease course in colorectal cancer would aid the development of improved treatment strategies. For this reason, we evaluated the prognostic value of flow cytometric DNA ploidy and S-phase fraction (SPF) and P-glycoprotein (Pgp) expression in this type of tumor.

METHODS

The prognostic significance of DNA ploidy, SPF, and Pgp expression on paraffin-embedded sections from 107 patients with colorectal carcinoma was determined. The mean follow-up was 36.6 months (range = 3-72 months). DNA ploidy and SPF were evaluated by flow cytometry and Pgp by immunohistochemistry using monoclonal antibody C219. The Cox regression model was used to adjust for several clinical and pathologic covariates.

RESULTS

Of the 107 carcinomas examined, 44 (41.1%) were classified as DNA diploid and 63 (58.9%) as DNA aneuploid. DNA ploidy pattern was significantly related to tumor site (P = 0.010), tumor stage (P = 0.016), and vascular invasion (P = 0.015) but not to other clinicopathologic variables. Patients with DNA diploid tumors showed a better survival rate than did those with aneuploid tumors. After stage IV disease was excluded, patients with diploid tumors also presented a better disease-free and overall survival than did patients with aneuploid tumors. Mean SPF of the whole series was 13.5% (median = 11.3%, range = 1.4%-29.9%). Aneuploid tumors had a higher median SPF than did diploid tumors (17 vs. 6.2; P = 0.0001). SPF was only related significantly with tumor location (P = 0.026). In the multivariate analysis, SPF was a significant independent prognostic factor for overall survival (P = 0.01). When stage IV was excluded, SPF was also an independent prognostic variable for both disease-free (P = 0. 02) and overall (P = 0.01) survival. Of 107 tumors, 61 (57%) were positive for Pgp expression, but no relation was found between this and other clinicopathologic parameters. Pgp expression had no influence on survival.

CONCLUSIONS

Our results suggest that flow cytometric DNA ploidy and SPF are significant and independent prognostic factors in patients with colorectal carcinoma, whereas Pgp expression is not.

Usefulness of proliferative activity, DNA ploidy pattern and p53 products as diagnostic adjuncts in colorectal adenomas and intramucosal carcinomas

Although numerous studies have assessed the biologic parameters of tumors, measurement of these parameters has had, to date, little impact on histologic diagnosis. Furthermore, analysis of a single parameter is insufficient to evaluate tumor malignant potential. In the present study, cell proliferation, DNA ploidy and p53 product were analyzed to objectify the tumor malignant potential in colorectal adenomas and intramucosal carcinomas. Sixty-one adenomas and 49 intramucosal carcinomas were studied using immunohistochemical analysis of Ki-67 and p53, silver-staining nucleolar organizer region (AgNOR) stain and DNA ploidy in fresh samples. Intramucosal carcinoma exhibited a greater Ki-67-positive rate and AgNOR count than the adenomas, although these parameters varied widely among samples. The incidence of aneuploidy and p53 over-expression in colorectal intramucosal carcinomas was significantly higher than in colorectal adenomas. These results indicate that DNA aneuploidy and p53 accumulation are the most reliable parameters for distinguishing benign and malignant lesions.

Distribution of carcinoembryonic antigen and biologic behavior in colorectal carcinoma

PURPOSE

Carcinoembryonic antigen is assumed from the results of several experiments to be associated with invasion of colorectal carcinoma by adhesion or contact inhibition. The patterns and the intensity of carcinoembryonic antigen distribution in colorectal carcinoma were assessed to verify whether they were correlated with malignant potential from those biologic characteristics.

METHODS

Carcinoembryonic antigen distribution was tested in the archival samples of 149 colorectal carcinomas by immunohistochemistry, using three characterized anti-carcinoembryonic antigen monoclonal antibodies: T84.66, PR1A3, and PR3B10. The distribution patterns in neoplastic tissue were categorized into unstained, apicoluminal, and diffuse cytoplasmic patterns. Tumor, invasive tumor margin, and tissue surrounding the tumor were examined.

RESULTS

Although all three antibodies revealed a positive correlation, T84.66 showed better discrimination than the others. Although none of the negative staining of the tumor or invasive tumor margin showed recurrence, the apicoluminal pattern showed recurrence, and the diffuse pattern showed the most frequent recurrence (P < 0.01). Recurrence was also associated with staining intensity in the apicoluminal pattern in both the tumor and invasive tumor margin (P < 0.05). Infiltrative tumor growth and lymph node metastasis were more frequent in cases of positive staining in tissue surrounding the tumor. Patients with the apicoluminal pattern achieved longer survival than patients with the diffuse-cytoplasmic pattern in the invasive tumor margin (P = 0.024) by a multivariate analysis including tumor stage and histologic differentiation.

CONCLUSION

The distribution of carcinoembryonic antigen in tumors and surrounding tissue seems to be closely correlated with invasiveness and metastatic behavior in colorectal carcinoma. Carcinoembryonic antigen immune staining can be considered as an efficient tool to determine groups with risk of recurrence.