Evaluation of heterogeneity of DNA ploidy in early gastric cancers.

DNA ploidy has been shown to be a predictive parameter for prognosis in various solid tumours. The prognostic value of DNA-ploidy in gastric cancers is still a matter of controversy. A possible explanation for the discrepant results reported in the literature could be sampling error in tumours with multiple stemlines differing in DNA-ploidy. In order to determine whether or not such heterogeneity exists in early gastric carcinoma, we have performed DNA cytophotometry on multiple samples of a group of 17 early gastric carcinomas, of which 8 were pure intramucosal and 9 were infiltrating into the submucosa. We found an aneuploid DNA-stemline in 8 (47%) early gastric cancers, more often in tumours invading into the submucosa (5/9) than in purely mucosal tumours (3/8). Multiple DNA-stemlines were found more frequently in submucosally infiltrating tumours (4/5). These results confirm the presence of DNA-aneuploid early gastric carcinoma which are frequently heterogeneous and suggest that heterogeneity occurs more frequently in tumours invading the submucosa. This heterogeneity is best detected by analysing multiple samples of tumours for DNA-ploidy.     

DNA ploidy of human breast cancer

Ploidy was determined on 663 resectable primary tumors from untreated patients. Nuclei obtained by mechanical disaggregation of frozen tissue were stained with propidium iodide and analysed in a FACS IV. Aneuploidy was detected in 73% of cases. It was not significantly related to nodal involvement or tumor size, although the highest frequencies were observed in large tumors (88%) or with more than 10 positive nodes (77%). Aneuploidy was more frequently observed in ductal infiltrating (81%) than in lobular histology and in tumors lacking both progesterone and estrogen receptors (85%). Analysis of ploidy in primary and synchronous lymph node metastases from the same patient showed a high agreement rate (90%) of DNA patterns simply defined as diploid or aneuploid. However, differences in DNA stemlines and DNA indices between the two synchronous lesions from the same patient were a rather frequent event.     

Cytometry and DNA ploidy: Clinical uses and molecular perspective in gastric and lung cancer

Flow cytometry is one of the most powerful and specific methods used for the integrated study of the molecular and morphological events occurring during cell proliferation. Many methods have been described for investigating this process. Several cell cycle regulators controlling the correct entry and progression through the cell cycle are altered in tumors. In fact, in most, if not all, human cancers there is a deregulated control of G1 phase progression, the period when cells decide if they will start proliferation or stay quiescent. Cytometry (flow and image) is able to analyze DNA content thanks to the use of the same “molecule” conjugates with a fluorochrome that permits to identify DNA content of single cell in a sample. Most important results of studies on DNA ploidy have been reviewed during the last years and as a result the analyses of DNA ploidy in cancer may provide clinically useful information on diagnostic, therapeutic and prognostic aspects. In fact, aneuploid cancer has a high proliferative activity and a metastatic or invasive potential, markers of a poor prognosis. Multiparametric flow cytometry should allow the simultaneous determination of morphology, phenotype, intracellular protein expression, and status of chromatin and DNA. Evaluating if a particular protein is responsible for the aggressiveness of cancer, or the alteration of DNA content, or if the activation of its state is the cause of rapid growth of cancer cells, is very important and it can facilitate the clinical treatment of patients. J. Cell. Physiol. 222: 532–539, 2010. © 2009 Wiley‐Liss, Inc.     

DNA ploidy and survival in breast cancer patients

Flow cytometric DNA ploidy measurements using frozen or deparaffinized tumor specimens were performed on 565 primary breast cancers from patients treated in the period 1975-1984. Twenty-nine percent of the cases were diploid, 61% had a single aneuploid stemline, and 10% were multiploid. Aneuploid tumors more often had negative estrogen receptor values than diploid tumors, but no significant correlation was found between ploidy class and TNM stage. Patients with more than ten positive axillary lymph nodes had predominantly aneuploid tumors. Overall and distant relapse-free survival were higher for patients with diploid tumors and low-aneuploid tumors. Stratification of the patients according to degree of lymph node involvement, TNM stage, and menopausal stage showed that the prognostic effect of aneuploidy was apparent predominantly in patients with locally advanced disease. Postmenopausal node-positive patients with diploid tumors had a significantly better prognosis than those with aneuploid tumors, but this difference was not found for the comparable premenopausal group. Multivariate analysis with the Cox proportional hazards model indicated that ploidy is an additional, independent prognostic factor in postmenopausal patients.     

DNA ploidy and markovian analysis of neoplastic progression in experimental pancreatic cancer.

Computer-assisted analysis of DNA ploidy and nuclear morphology were used to elucidate changes in the cell nucleus that occur during the development of experimental pancreatic cancer. Ductal pancreatic adenocarcinoma was induced in 49 Syrian hamsters by SC injection of N-nitrosobis (2-oxopropyl) amine; twenty hamsters served as controls. Groups of animals were sacrificed every 4 weeks for 20 weeks and adjacent sections of pancreatic tissue were H&E and Feulgen-stained for light microscopy and computer assisted cytometry. Pancreatic ductal cells were classified as normal, atypical, or malignant; tissue inflammation (pancreatitis) was also noted when present. DNA ploidy and nuclear morphology evaluation (Markovian analysis) identified an atypical cell stage clearly distinguishable from either normal or malignant cells; pancreatitis preceded this atypia. The DNA ploidy histogram of these atypical cells revealed a major diploid peak and a minor aneuploid peak. The receiver operator characteristic curve areas for a logistic regression model of normal vs atypical cells was 0.94 and for atypical vs malignant was 0.98, numbers indicative of near-perfect discrimination among these three cell types. The ability to identify an atypical cell population should be useful in establishing the role of these cells in the progression of human pancreatic adenocarcinoma.     

Intratumoral variations in DNA ploidy and s-phase fraction in human breast cancer.

To study intratumoral DNA ploidy heterogeneity and S-phase fraction (SPF) variability, we prospectively collected five different samples from 48 breast carcinomas and each sample was analysed separately by flow cytometry. Aneuploidy rate was 89.6% after analysis of four or five samples. DNA ploidy heterogeneity, i.e., different samples classified as either DNA euploid or DNA aneuploid in the same tumor was seen in 17%, and DNA index heterogeneity, i.e., tumor populations with different DNA indices (DIs) seen in different samples was 44%. A statistical model defining SPF heterogeneity is proposed. SPF heterogeneity as defined by us was 71%, and as expected the SPF heterogeneity rate increased significantly with increasing number of analysed samples. Four or more samples are needed to detect the most deviant (highest) SPF values. An unrecognized intratumor heterogeneity of DNA ploidy and SPF may partly explain the conflicting results reported in the literature on the above prognostic indicators.     

DNA ploidy and vimentin expression in primary breast cancer

DNA ploidy and vimentin expression in primary breast cancer
The DNA content of 50 breast cancers of varying tumour type, grade and stage was measured using static image cytometry, and correlated with vimentin expression in the tumour cells. A tendency to increased vimentin expression and aneuploidy was observed in high grade and late stage tumours¹. A statistically significant difference was observed in DNA index and ploidy balance between grade 1 and grades 2 and 3 carcinomas ( P <0.05) and between stage I and stage II carcinomas ( P <0.05). There was a significant difference in the expression of vimentin between grades 1, 2, 3 ( P <0,001), and stages I, II and III ductal carcinomas ( P <0.05). No significant difference was observed in the proliferation index and the degree of hyperploidy ( P >0.05). Clonal heterogeneity was observed in 25% of breast carcinomas, and was associated with increased vimentin expression. These changes may be indicative of genomic alteration and tumour aggressiveness.     

DNA ploidy of bladder cancer using bladder biopsy supernate specimens

OBJECTIVE: To perform DNA image cytometry on 119 bladder biopsy supernate (BBS) specimens of transitional cell carcinoma (TCC) bladder to: (1) test the suitability of this cytologic specimen for use in DNA ploidy analysis, and (2) assess the value of DNA ploidy measured on this specimen as to the risk of tumor recurrence and survival. STUDY DESIGN: The histologic grade and cytologic grade were correlated, and the DNA ploidy produced was determined by image analysis of Feulgen-stained nuclei. Kaplan-Meier curves related age, sex, grade and DNA ploidy to recurrence of tumor and survival. Log rank analyses were used to ascertain the difference between the curves for each categorical variable. RESULTS: Urothelial cells derived from the BBS specimen were demonstrated to be representative of the tumor. The tumor recurrence rate was significantly higher (P = .0001) and the survival rate significantly lower (P = .0002) for patients with aneuploid tumors compared to those with diploid tumors. Patients with TCC 2 tumors had a significantly shorter time to recurrence (P = .003), although the relationship between ploidy and survival in this group was of marginal significance. CONCLUSION: The specimen was free of many of the problems associate with the other specimen types used for measuring DNA ploidy. The results show that the BBS specimen is diagnostically useful and suitable for DNA analysis, providing prognostically relevant information.     

Cytofluorimetric evaluation of DNA ploidy in lung cancer: a bronchoscopic study

The study of the biological characteristics of lung cancer is gaining more and more interest both because of their potential role as prognostic indicators and for therapeutic reasons. The DNA content estimated by flow cytometry in surgical samples of non-small cell lung cancer (NSCLC) has already been demonstrated to be correlated with survival in these patients. From July 1990 to February 1992 we analyzed the DNA distribution of bronchoscopic biopsies from 88 patients with lung cancer (18 small cell lung cancer, SCLC, and 68 NSCLC, two unspecified histology). Twenty-eight tumors (34.6%) had a diploid DNA distribution, while 53 were aneuploid (65.4%). A correlation was found between DNA ploidy and survival. Evaluation of the DNA content in bronchoscopic samples in a large series of patients could determine the role of this analysis prior to surgery in NSCLC and its value as a marker with respect to prognosis and response to therapy in SCLC.     

DNA ploidy pattern and amplification of ERBB and ERBB2 genes in human gastric carcinomas

The DNA ploidy pattern and amplification of ERBB and ERBB2 genes were examined in paraffinembedded tissue from gastric carcinomas using flow cytometry and a slot-blot hybridization technique. The incidence of aneuploidy in well differentiated adenocarcinomas (56%) was significantly higher (p<0.05) than that in poorly differentiated adenocarcinomas (21%). The DNA ploidy pattern was not remarkably different between the primary tumors and metastatic deposits in lymph nodes. Of the nine specimens having an aneuploid stem cell line in the primary tumor and/or in metastases, three showed ERBB2 gene amplification and one showed ERBB gene amplification. The incidence of epidermal growth factor (EGF) immunoreactivity in tumor cells showed no difference between diploid and aneuploid tumors. These findings indicate that aneuploidy is frequently associated with amplification of ERBB and ERBB2 genes.     

DNA ploidy pattern and amplification of ERBB and ERBB2 genes in human gastric carcinomas

The DNA ploidy pattern and amplification of ERBB and ERBB2 genes were examined in paraffin-embedded tissue from gastric carcinomas using flow cytometry and a slot-blot hybridization technique. The incidence of aneuploidy in well differentiated adenocarcinomas (56%) was significantly higher (p less than 0.05) than that in poorly differentiated adenocarcinomas (21%). The DNA ploidy pattern was not remarkably different between the primary tumors and metastatic deposits in lymph nodes. Of the nine specimens having an aneuploid stem cell line in the primary tumor and/or in metastases, three showed ERBB2 gene amplification and one showed ERBB gene amplification. The incidence of epidermal growth factor (EGF) immunoreactivity in tumor cells showed no difference between diploid and aneuploid tumors. These findings indicate that aneuploidy is frequently associated with amplification of ERBB and ERBB2 genes.     

HER-2/neu oncogene expression, DNA ploidy and proliferation index in breast cancer.

HER-2/neu gene expression, DNA ploidy and proliferation index were studied in 250 cases of breast cancer. Expression of HER-2/neu was determined by using an antibody to the HER-2/neu receptor. Ki-67 antibody was used to determine the proliferation index of the breast cancers, and the Feulgen method was used to assess DNA amounts in the tumor cells. Histochemical staining was quantitated by image analysis. Of the cancers studied, 72 were positive for overexpression of HER-2/neu protein; of these, 62 (86%) possessed near-tetraploid DNA content, and 47 (65%) had more than one G0G1 stem line (polyploid) of DNA distribution. Cells from the cases negative for HER/2-neu overexpression contained DNA amounts that ranged from diploid to varying degrees of aneuploid. A significant difference in the amounts of cellular proliferation in HER-2/neu overexpressing cancers was found between those that expressed the HER-2/neu receptor on their membranes and those that exhibited mainly cytoplasmic receptors.     

Comparison of the intratumor DNA ploidy distribution pattern between differentiated and undifferentiated gastric carcinoma

OBJECTIVE: To compare the differences in intratumor DNA ploidy distribution pattern between differentiated and undifferentiated carcinoma of the stomach. STUDY DESIGN: Two hundred five cases of surgically resected gastric carcinoma were studied, comprising 125 differentiated and 80 undifferentiated carcinomas. DNA ploidy was determined by means of flow cytometry in stepwise sections of the entire tumor. The intratumor DNA ploidy distribution pattern was compared between these two histologic types. RESULTS: Differentiated carcinomas comprised 35 cases of predominantly diploid (28%) and 90 cases of predominantly aneuploid (72%) tumors, while undifferentiated carcinomas comprised 46 cases of predominantly diploid (57.5%) and 34 cases of predominantly aneuploid (42.5%) (P < .01). The frequency of cases showing predominantly aneuploidy among the differentiated carcinomas was significantly higher than among the undifferentiated carcinomas at stages IA and IIIA. The rate of cases showing heterogeneity was lower among the early-stage cases than among the advanced-stage cases in both histologic types. Among the differentiated carcinomas, there were 22 cases that had more than six DNA stemlines in each tumor, whereas among undifferentiated carcinomas, there were six such cases (P < .05). CONCLUSION: There were more cases with high malignant potential among the differentiated carcinoma cases than among the undifferentiated carcinoma cases in the present series.     

Correlation of protein expression, Gleason score and DNA ploidy in prostate cancer

The prognosis of prostate cancer correlates with tumor differentiation. Gleason score and DNA ploidy are two prognostic factors that correlate with prognosis. We analyzed differences in protein expression in prostate cancer of high and low aggressiveness according to these measures. From 35 prostatectomy specimens, 29 cancer samples and 10 benign samples were harvested by scraping cells from cut surfaces. DNA ploidy was assessed by image cytometry. Protein preparations from cell suspensions were examined by 2-DE. Protein spots that differed quantitatively between sample groups were identified by MS fingerprinting of tryptic fragments and MS/MS sequence analysis. We found 39 protein spots with expression levels that were raised or lowered in correlation with Gleason score and/or DNA ploidy pattern (31 overexpressed in high-malignant cancer, 8 underexpressed). Of these, 30 were identified by MS. Among overexpressed proteins were heat-shock, structural and membrane proteins and enzymes involved in gene silencing, protein synthesis/degradation, mitochondrial protein import (metaxin 2), detoxification (GST-pi) and energy metabolism. Stroma-associated proteins were generally underexpressed. The protein expression of prostate cancer correlates with tumor differentiation. Potential prognostic markers may be found among proteins that are differentially expressed and the clinical value of these should be validated.     

DNA ploidy measurements in tissue sections

Nuclear DNA ploidy measurements based on tissue sections, although technically tedious and time consuming, can provide useful diagnostic and prognostic information. Methods for minimizing distributional errors and optimizing interpretation of DNA histograms are presented, and the diagnostic and prognostic significance of DNA ploidy measurements in gynecologic cancer and its precursors is reviewed.     

DNA ploidy pattern and S-phase characteristics of metastatic melanoma.

Samples of 130 metastatic melanomas from 92 patients were analyzed by DNA flow cytometry. DNA aneuploidy was observed in 67% of the patients. DNA indices were evenly distributed from 0.6 to 2.6 Tumors originating from primary lesions in the lower extremities were more frequently DNA aneuploid than those of other sites. S-phase fraction (SPF) was evaluable from 73 tumors. DNA aneuploid tumors had a significantly higher SPF than diploid tumors, and females had a higher SPF than males. Furthermore, distant metastases had a higher SPF than metastases in regional lymph nodes and in transit metastases, probably indicating a higher growth potential in metastases spreading to distant sites.     

Prospective study on prognostic significance of DNA ploidy and Ki-67 expression in colorectal cancer

The aim of the study was to correlate tumoral DNA ploidy and Ki-67 expression with therapy response, Overall Survival (OS), Disease Specific Survival (DSS) and Disease Free Survival (DFS). Three samples of colorectal cancer were collected from each patient. One sample of normal tissue was our internal control. DNA ploidy was evaluated by FACSCalibur cytometer and Ki-67 by immunohistochemistry. We studied 67 patients and we found aneuploidy in 65,7 percent of carcinoma with a Ki-67 median expression of 55 percent. After surgery and chemotherapy in 35 percent of the patients with aneuploid carcinoma and high proliferative activity (Ki-67 greater than 55 percent) there were no evidence of disease versus 100 percent of patients with DNA diploidy and low proliferative activity (Ki-67 less than 55 percent). Tumoral aneuploidy significantly correlated with lower OS, DSS and DFS (18 percent vs 86 percent at 30 months). Univariated analysis demonstrated a significant correlation between aneuploidy and develop disease progression (p=0,033, odd ratio=5.7), while the cut-off of 55 percent for Ki-67 expression did not correlate with OS, DSS and DFS. Preliminary results (the study is still in progress) seemed to suggest that DNA ploidy has a prognostic and predictive significance in colorectal carcinoma.     

Colorectal carcinoma. DNA ploidy pattern and prognosis with reference to tumor DNA heterogeneity.

Nuclear DNA content was measured in 72 colorectal carcinomas using single-cell microspectrophotometry on Feulgen-stained smears. Four samples were analyzed from each tumor. Patients were followed for 41-65 months (average, 53). DNA heterogeneity (both aneuploid and nonaneuploid patterns) was present in 44% of the cases. Sixty-eight percent of the tumors showed an aneuploid DNA pattern in at least one of the samples. Patients with nonaneuploid tumors tended to have a survival advantage over patients with homogeneously aneuploid tumors and demonstrated a significantly longer disease-free survival. The DNA ploidy pattern is of potential value in conjunction with histopathologic prognostic parameters in colorectal carcinoma. Since colorectal tumors exhibit pronounced DNA heterogeneity, multiple samples are required from each tumor to permit a proper evaluation of its DNA pattern. The DNA heterogeneity may represent tumor progression and can partly explain the conflicting results reported concerning DNA pattern and prognosis in colorectal carcinoma.