Gastric cancer heterogeneity

Expression heterogeneity of ABC-transporter family genes and chemosensitivity genes in gastric tumor, carcinomatosis and lymph node metastases

Introduction. Metastatic tumors (particularly gastric cancer) have been found to be characterized by heterogeneity between the primary tumor and metastases. This type of heterogeneity comes to the fore when treating primary-metastatic forms of tumor and is an important reason for the low effectiveness of their treatment. In this regard, comparative analysis of ABC-transporter gene expression and chemosensitivity genes will allow to characterize to a certain extent the resistance and sensitivity of primary tumor, carcinomatosis and metastases to therapy and provide the basis for personalized treatment approach.Aim. To evaluate expression heterogeneity of ABC-transporter genes and chemosensitivity genes in gastric tumor, carcinomatosis and lymph node metastases.Materials and methods. Overall 41 patients with disseminated gastric cancer stage IV with carcinomatosis of peritoneum were included in the investigation. All patients underwent surgery according to Roux palliative gastrectomy. After surgery patients underwent chemotherapy depending on indications. RNA was isolated using RNeasy Plus mini kit (Qiagen, Germany). The expression level of ABC transporter genes (ABCB1, ABCC1, ABCC2, ABCC5, ABCG1, ABCG2) and chemosensitivity genes (BRCA1, RRM1, ERCC1, TOP1, TOP2α, TUBβ3, TYMS, GSTP1) was assessed by reverse transcription polymerase chain reaction (RT-PCR) in primary tumor, carcinomatosis and lymph node metastases.Results. The expression levels of the genes under study were shown to vary widely. For ABC transporter genes, ABCG1 (3.1 ± 1.1; max 32.0), ABCG2 (7.9 ± 2.3; max 54.1), ABCG2 (9.6 ± 3.8; max 101.0) were the most expressed genes in gastric tumor tissue, carcinomatosis and lymph node metastasis, respectively. Hyperexpression among chemosensitivity genes at all three sites was characteristic only of TOP2α (17.2 ± 6.0; max. 161.9; 10.8 ± 4.1; max. 105.1; 35.3 ± 0.8; max. 439.6, respectively). We found that TOP2α and BRCA1 gene expression levels were higher in lymph node metastasis compared with gastric tumor tissue and carcinomatosis (at p = 0.005 and p = 0.001). Whereas ABCC1 gene expression was statistically significantly higher in carcinomatosis (p = 0.03).Conclusion. Thus, a high level of expression heterogeneity is observed in gastric cancer, which affects the expression patterns of various genes in different localizations. The expression profile can be used to determine the level of heterogeneity and approach to personalized therapy tactics.

Identifying heterogeneous subtypes of gastric cancer and subtype‑specific subpaths of microRNA‑target pathways

The present study aimed to classify gastric cancer (GC) into subtypes and to screen the subtype-specific genes, their targeted microRNAs (miRNAs) and enriched pathways to explore the putative mechanism of each GC subtypes. The GSE13861 data set was downloaded from the Gene Expression Omnibus and used to screen differential expression genes (DEGs) in GC samples based on the detection of imbalanced differential signal algorithm. The specific genes in each subtype were identified with the cut-off criterion of U>0.04, pathway enrichment analysis was performed and the subtype-specific subpaths of miRNA-target pathway were determined. A total of 1,263 DEGs were identified in the primary gastric adenocarcinoma (PGD) samples, which were subsequently divided into four subtypes, according to the hierarchy cluster analysis. Identification of the subpaths of each subtype indicated that the subpath related to subtype 1 was miRNA (miR)-202/calcium voltage-gated channel subunit α1 (CACNA1E)/type II diabetes mellitus. The nuclear factor-κB signaling pathway was the most significantly specific pathway and subpath identified for subtype 2, which was regulated by miR-338-targeted suppression of C-C motif chemokine ligand 21 (CCL21). For subtype 3, significant related pathways included ubiquitin-mediated proteolysis and proteasome, and the important subpath was miR-146B/proteasome 26S subunit, non-ATPase 3 (PSMD3)/proteasome; focal adhesion was the significant pathway indicated for subtype 4, and the subpaths were miR-34A/vinculin (VCL)/focal adhesion and miR-34C/VCL/focal adhesion. In addition, Helicobacter pylori infection was higher in GC subtype 1 than in other subtypes. Specific genes, such as CACNA1E, CCL21, PSMD3 and VCL, may be used as potential feature genes to identify different subtypes of GC, and their associated subpaths may partially explain the pathogenetic mechanism of each GC subtype.

Intra-Tumoral Heterogeneity of HER2, FGFR2, cMET and ATM in Gastric Cancer: Optimizing Personalized Healthcare through Innovative Pathological and Statistical Analysis

Current drug development efforts on gastric cancer are directed against several molecular targets driving the growth of this neoplasm. Intra-tumoral biomarker heterogeneity however, commonly observed in gastric cancer, could lead to biased selection of patients. MET, ATM, FGFR2, and HER2 were profiled on gastric cancer biopsy samples. An innovative pathological assessment was performed through scoring of individual biopsies against whole biopsies from a single patient to enable heterogeneity evaluation. Following this, false negative risks for each biomarker were estimated in silico. 166 gastric cancer cases with multiple biopsies from single patients were collected from Shanghai Renji Hospital. Following pre-set criteria, 56 ~ 78% cases showed low, 15 ~ 35% showed medium and 0 ~ 11% showed high heterogeneity within the biomarkers profiled. If 3 biopsies were collected from a single patient, the false negative risk for detection of the biomarkers was close to 5% (exception for FGFR2: 12.2%). When 6 biopsies were collected, the false negative risk approached 0%. Our study demonstrates the benefit of multiple biopsy sampling when considering personalized healthcare biomarker strategy, and provides an example to address the challenge of intra-tumoral biomarker heterogeneity using alternative pathological assessment and statistical methods.

Hypoxia-mediated CD24 expression is correlated with gastric cancer aggressiveness by promoting cell migration and invasion

CD24 is a heavily glycosylated cell surface protein that is expressed in putative stem cells and is overexpressed in various human malignancies, yet the significant roles of CD24 in gastric cancer development are still elusive. We investigated the involvement of CD24 in gastric cancer aggressiveness, which is attributed to its heterogeneity. Cultured gastric cancer cells showed diverse expression patterns in CD24, whereas other defined cell surface markers, such as CD44 and CD133, were homogenous. Purely sorted CD24-negative gastric cancer cells showed strong alteration into the CD24-positive cell type in an autochthonous manner, and reached to steady expression levels. Our clinicopathological study revealed that CD24 positivity was an independent prognostic factor in both intestinal and diffuse types of gastric cancer. CD24 expression was correlated with the advanced stages, invasiveness, and lymph node metastasis of gastric cancer. Silencing of CD24 in cultured cells significantly decreased cell migration and invasion. Hypoxic treatment upregulated CD24 expression, and simultaneously induced cell motility and invasion of gastric cancer cells. Hypoxic treatment-induced CD24 expression was significantly attenuated by knockdown of hypoxia-inducible transcription factors. These data suggest that CD24-negative cells are capable of gaining cell motility and invasiveness through the induction of CD24, which is mediated by hypoxia. CD24 would be an attractive marker to define not only the heterogeneity but also the aggressiveness of gastric cancer cells. The mechanisms by which hypoxia induces CD24 expression would also be a potential therapeutic target for gastric cancer.

FGFR2, HER2 and cMet in gastric adenocarcinoma: detection, prognostic significance and assessment of downstream pathway activation

Receptor tyrosine kinase pathways are potential therapeutic targets in gastric adenocarcinoma patients. We evaluated HER2 and cMet protein expression, and FGFR2 gene amplification to assess their prognostic significance, and downstream mediators pS6 and pERK for their potential utility as pharmacodynamic biomarkers in patients with gastric adenocarcinoma. Tissue microarrays were constructed from resection samples of 184 patients who underwent surgery for gastric/gastro-oesophageal junction adenocarcinoma. Tissue cores were obtained from the tumour body (TB), luminal surface (LS) and invasive edge (IE), and immunohistochemical and fluorescence in situ hybridisation (FGFR2) analysis was performed. FGFR2 amplification was identified in 2 % of cases and associated with worse survival (P = 0.005). HER2 overexpression was observed in 10 % of cases and associated with increased survival (P = 0.041). cMet overexpression was observed in 4 % of cases and associated with worse survival (P < 0.001). On multivariate analysis, only cMet retained significance (P = 0.006). pS6 and pERK expression were observed in 73 % and 30 % of tumours, respectively, with no association with survival. HER2 (P = 0.004) and pERK (P = 0.001) expression differed between tumour regions with HER2 expression increased in the LS compared with the TB and IE. These findings confirm subpopulations in gastric adenocarcinoma with poor outcome that may benefit from specific therapeutic strategies. However, we found heterogeneous HER2, pS6 and pERK overexpression, which presents challenges for their use as predictive biomarkers in gastric biopsies. The potential downstream pharmacodynamic markers pS6 and pERK were expressed across tumour regions, providing evidence that resections and biopsies would yield comparative results in clinical trials.

Evaluating tumor heterogeneity in immunohistochemistry-stained breast cancer tissue

Quantitative clinical measurement of heterogeneity in immunohistochemistry staining would be useful in evaluating patient therapeutic response and in identifying underlying issues in histopathology laboratory quality control. A heterogeneity scoring approach (HetMap) was designed to visualize a individual patient's immunohistochemistry heterogeneity in the context of a patient population. HER2 semiquantitative analysis was combined with ecology diversity statistics to evaluate cell-level heterogeneity (consistency of protein expression within neighboring cells in a tumor nest) and tumor-level heterogeneity (differences of protein expression across a tumor as represented by a tissue section). This approach was evaluated on HER2 immunohistochemistry-stained breast cancer samples using 200 specimens across two different laboratories with three pathologists per laboratory, each outlining regions of tumor for scoring by automatic cell-based image analysis. HetMap was evaluated using three different scoring schemes: HER2 scoring according to American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) guidelines, H-score, and a new continuous HER2 score (HER2(cont)). Two definitions of heterogeneity, cell-level and tumor-level, provided useful independent measures of heterogeneity. Cases where pathologists had disagreement over reads in the area of clinical importance (+1 and +2) had statistically significantly higher levels of tumor-level heterogeneity. Cell-level heterogeneity, reported either as an average or the maximum area of heterogeneity across a slide, had low levels of dependency on the pathologist choice of region, while tumor-level heterogeneity measurements had more dependence on the pathologist choice of regions. HetMap is a measure of heterogeneity, by which pathologists, oncologists, and drug development organizations can view cell-level and tumor-level heterogeneity for a patient for a given marker in the context of an entire patient cohort. Heterogeneity analysis can be used to identify tumors with differing degrees of heterogeneity, or to highlight slides that should be rechecked for QC issues. Tumor heterogeneity plays a significant role in disconcordant reads between pathologists.

Expression of P53 Protein and Dna Flow Cytometry in Gastric Adenocarcinoma: Implications in Patients Treated with Adjuvant Etoposide, Adriamycin and Cisplatin

Aims and background

We evaluated the prognostic value of p53 protein, DNA content and S-phase fraction in patients with adenocarcinoma of the stomach or the gastroesophageal junction treated with adjuvant etoposide, doxorubicin and cisplatin.

Methods and study design

Thirty-five consecutive patients with stage II or III gastric or gastroesophagial junction adenocarcinoma treated with at least two cycles of adjuvant etoposide, doxorubicin and cisplatin after curative gastric resection were included. The expression of p53 protein was determined by immunohistochemistry and DNA content by flow cytometry. The presence of p53 expression and DNA content was compared with clinicopathological features.

Results

Median age was 54 years (range, 31–71). P53 expression was detected in 42.9% (15 of 35) of gastric cancer tissues of the patients. Aneuploidy was observed in 31.4% of patients, and S-phase fraction was more than 10% in 22.9%. P53 immunoreactivity (33.3% vs 47.8%) was more common in advanced disease. There was no association among p53 immunoreactivity, DNA content and S-phase fraction. We also found no significant relationship between p53 immunoreactivity, DNA content, S-phase fraction or other clinicopathological parameters. In univariate analysis, the involvement of lymph nodes was a significant predictor of a poor outcome (P = 0.001). Also, p53-positive patients had a poor survival close to the level of significance (P = 0.051). Likewise, p53 immunoreactivity (P = 0.0071), in addition to lymph node involvement (P = 0.0016), were the independent prognostic factors in multivariate analysis.

Conclusions

This trial supports the results of previous reports that p53 immunoreactivity is a prognostic factor for patients with adenocarcinoma of stomach or gastroesophageal junction treated with adjuvant chemotherapy.

DNA ploidy and its clinical implications in gastric cancer

BACKGROUND

Biological characteristics of gastric cancer depend mostly on genetic alterations in the cancer cells of individuals. To precisely predict the biological behavior and clinical outcome of individual cancer, it may be important to clarify the DNA profiles of cancer cells in each case.

METHODS

We have reviewed the most important results of studies on DNA ploidy of gastric cancer published in the English literature during the last 2 decades.

RESULTS

Gastric carcinoma with aneuploidy has been shown to have a high proliferative activity and a high metastatic or invasive potential, thus leading to a poor prognosis as compared to diploid tumors.

CONCLUSION

Analyses of DNA ploidy in gastric cancer may provide clinically useful information on diagnostic, therapeutic, and prognostic aspects. Further investigations may be needed to clarify the relationship between chromosome instability and DNA ploidy.

Prognostic value of DNA flow cytometry in stomach cancer: a 5-year prospective study

The role of DNA flow cytometry in the prediction of prognosis for patients with stomach cancer remains to be defined. Thus we studied prospectively the role of DNA flow cytometry as a prognosis indicator in stomach cancer patients in a high-incidence area. Between November 1990 and December 1992, primary stomach cancer tissues were obtained from the surgical specimens from 217 patients (148 male, 69 female). DNA flow cytometric analyses of DNA ploidy and S-phase fraction were performed and the results were correlated with patient survival. The median age of the patients was 55 years (range 24-78). Aneuploid cell population was found in 114 of 217 samples (53%). Tumour S-phase fraction was obtained in 96 of 103 diploid tumours (93%) and 61 of 114 aneuploid tumours (54%). After median follow-up of 66.1 months, the patients with tumours with an S-phase fraction over 17% had significantly worse survival rates than patients with tumours with S-phase fractions of lower than 8% or 8-17% (45% vs 59% and 63% of patients surviving, P = 0.007). Tumour ploidy status did not correlate with patient survival. Multivariate analyses showed that the TNM stage remained the most important prognostic indicator. The tumour S-phase fraction was also an independent prognostic indicator (relative risk 2.300, 95% CI, 1.252-4.223). Tumour S-phase fraction obtained by DNA flow cytometry is an independent prognostic indicator for the survival of the patients with stomach cancer.

Cytogenetic heterogeneity and histologic tumor growth patterns in prostatic cancer

Twenty-five prostatic adenocarcinomas were studied for the presence of intratumoral cytogenetic heterogeneity by interphase in situ hybridization (ISH) to routinely processed tissue sections. ISH with a chromosome Y-specific repetitive DNA probe provided a model to investigate patterns of chromosomal heterogeneity within and between different pathological grades. The Gleason grading system was used, since it is based on a detailed classification of growth patterns. Heterogeneity with respect to ploidy of the tumor was examined by ISH with a repetitive DNA probe specific for chromosome 1. The ploidy status of these cancers was confirmed by DNA flow cytometry (P < 0.001). Cytogenetic heterogeneity at the (Y) chromosomal level was observed between Gleason areas, within one area, and even within single tumor glands. The different patterns of chromosomal heterogeneity were seen in all tumor grades and stages. Differences in ploidy status were also found following the aforementioned histological patterns, again, in all grades and stages. Intraglandular heterogeneity was most frequently seen. No correlation was found between cytogenetic heterogeneity and proliferative activity (Ki-67 immunostaining). In contrast to current views on clonality, suggesting regional separation of subclones with different DNA content, this study demonstrates that these subclones can be interspersed.

Correlation of DNA content between endoscopic biopsy and surgically resected specimens in gastric and colorectal cancer

To investigate DNA heterogeneity and the consistency of DNA content between endoscopic biopsy and the corresponding resected specimens, the DNA content of 749 different samples from 30 gastric and 30 colorectal cancers was analyzed and the results were compared with those obtained from endoscopic biopsy specimens. The incidence of DNA heterogeneity was 33% in patients with gastric cancer and 40% in those with colorectal cancer. Most of the cases of heterogeneity were caused by differences in DNA indices in aneuploidy. The consistency of DNA ploidy pattern between endoscopic biopsies and the corresponding resected specimens was 100% in both gastric and colorectal cancer, while the consistency in the DNA index of aneuploid tumors was approximately 90%. From these results, it seems possible that analysis of the DNA content of a biopsy specimen could provide an adequate measure of the DNA content of the corresponding resected specimen.

Flow cytometric analysis of DNA heterogeneity in superficial carcinoma of the esophagus

BACKGROUND

There are few studies of flow cytometric analysis for DNA heterogeneity of patients with superficial carcinoma of the esophagus limited to the epithelium or superficially invading the lamina propria or submucosa.

METHODS

Flow cytometric analysis of cellular DNA content was performed on superficial carcinomas of the esophagus using paraffin embedded blocks of the surgically resected specimens from 56 patients. To evaluate the intratumoral DNA heterogeneity, a total of 141 samples of the 56 tumors were analyzed, depending upon the tumor size.

RESULTS

One or two of the samples was available from 18 of 19 patients with tumors 2 cm or less in greatest dimension, whereas more than three of the samples were available from 22 of 37 patients with tumors 2.1 cm or greater in dimension (P < 0.003). Of 56 tumors, 40 (71.4%) exhibited DNA aneuploidy; DNA heterogeneity was found in 26 tumors (46.4%). The remaining 16 tumors exhibited DNA diploidy. Two of the five tumors that were limited to the epithelium had DNA heterogeneity. The mean dimension of the tumors with DNA heterogeneity was significantly greater (5.8 +/- 2.8 cm) than those exhibiting DNA diploidy (2.3 +/- 1.1 cm) and DNA aneuploidy without heterogeneity (2.9 +/- 2.4 cm). Recurrences after esophagectomy were detected in 6 of the 56 patients; the DNA ploidy pattern of these six patients exhibited DNA heterogeneity.

CONCLUSION

The incidence of DNA heterogeneity increases as tumor size increases and is associated with an increased risk of tumor recurrence after esophagectomy in patients with superficial carcinoma of the esophagus.

Effects of preoperative chemotherapy on DNA ploidy patterns, cell cycle, and histological findings in gastric and colonic cancer patients

The effects of preoperative chemotherapy on gastric and colonic cancers have yet to be evaluated fully. In this study, its effects were assessed by studying DNA ploidy patterns, cell cycles, and histological findings in such patients. Thirty-nine patients with gastric or colonic cancer were given preoperative chemotherapy with UFT (an admixture of tegafur and uracil). Biopsy specimens for analysis were obtained before chemotherapy through a gastroscope or colonoscope and after chemotherapy from resected tumors. The DNA ploidy patterns and cell cycles were evaluated using a flow cytometer and the tissues were examined histologically. The DNA ploidy pattern was diploid (D) in 12 gastric and 13 colonic cancer patients and aneuploid (A) in 10 and 4 patients, respectively. After chemotherapy, the pattern changed in nine gastric (A-->D: 7, D-->A: 2) and six colonic cancer patients (A-->D: 3, D-->A: 3) and was unchanged in the remaining patients. Cell cyclic analysis showed decreased G1- and increased S-phase fractions in 10 of 12 patients with gastric and 6 of 10 patients with colonic cancer. Histologically, decreased tumor cellularity, increased fibrosis, and/or cytological changes were observed in both cancers after chemotherapy. Gastric and colonic cancers in which the DNA ploidy pattern changed from aneuploid to diploid, G1- decreased and S-phase increased, and/or histological changes were observed, were considered to have responded to preoperative UFT administration.

Near-diploid transitional cell carcinoma: a preliminary report

DNA ploidy analysis has been accepted as an important prognostic factor for patients with transitional cell carcinoma (TCC). However, there was few information dealing with the clinical relevance of slightly aberrant DNA content by flow cytometry (FCM). Here we present five cases of near-diploid (ND) tumours, with DNA index (DI) varying from 0.92 to 1.14, obtained from a prospective study of fifty-one cases (9.8%). The frequency of ND tumours showed a tendency to decrease with increasing tumour stage. Higher fraction of tumour proliferation, defined by Ki-67 index, showed a steady increment from 3.4 to 23.5% with occurrence of gross chromosomal changes. In contrast, the expression of epidermal growth factor receptor (EGFR) decreased from 48.3 to 35.3% for diploid (n = 29) through aneuploid (n = 17) tumours. All three ND bladder cancers had recurrence of one to three times with median follow-up of 36 months. The incidences of tumour recurrence (60%) and cancer death (20%) in ND tumours were intermediate between the aneuploid and diploid TCCs. But, flow DNA analysis of paraffin-embedded ND tumours revealed wide and symmetrical G0/G1 peak with DI varying from 5.6 to 13.0. Our limited experience suggests the necessity of special treatment for G0/G1 peaks having CV values greater than 5.5% from paraffin-embedded urothelial carcinomas.

DNA ploidy and biologic aggressiveness of gastric adenocarcinoma in Chinese

The mortality rate of gastric cancer in the Chinese population has reached a plateau. The main prognostic factor for gastric adenocarcinoma is recognized as tumor stage. Recently, abnormalities in DNA content have been considered as a new prognostic factor. Whether abnormal DNA content can be used as a prognostic tool for Chinese patients with gastric cancer is unknown. To investigate this relation DNA ploidy and prognosis of gastric cancer patients were studied using paraffin-embedded specimens. A group of 104 newly diagnosed and surgically resected gastric cancer specimens obtained from January 1984 to December 1986 were examined for DNA content by flow cytometry. The quality of flow cytometry was acceptable with a mean coefficient of variance of 5.45. The results showed that 38 cases (36.5%) had DNA aneuploidy; 42 cases had metastatic lymph nodes with enough tumor cells, and 31.0% of these cases had DNA aneuploidy. DNA aneuploidy of primary tumors was correlated to lymph node metastasis and patient's age, whereas DNA aneuploidy of metastatic lymph nodes was significantly correlated to the serosal invasion of the gastric wall at the primary site. The important parameters for prognosis were curability of surgical resection, serosal invasion, tumor size, and distant metastasis. DNA aneuploidy of both primary tumors or metastatic lymph nodes appeared to be unrelated to the prognosis of gastric adenocarcinoma in Chinese patients. We therefore propose that DNA aneuploidy of gastric cancer is associated with tumor growth but not biologic aggressiveness.

DNA stem line heterogeneity in esophageal cancer accurately identified by flow cytometric analysis

BACKGROUND

This study was designed to evaluate the importance of DNA stem line heterogeneity in determining the malignant potential of esophageal cancer.

METHODS

Flow cytometric analysis of intratumor heterogeneity of DNA contents was performed on step-sectioned slices of 57 resected esophageal carcinomas.

RESULTS

DNA stem line heterogeneity, as assessed by DNA content measurements, was present in 25 (44%) tumors; 6 (11%) were a combination of diploid and aneuploid DNA pattern, and 19 (33%) had two or more aneuploid peaks with different DNA contents (multiploid). Of the remaining 32 homogeneous tumors, 4 showed only a diploid DNA pattern in all samples examined, whereas 28 tumors had only the aneuploid pattern. Tumors with the heterogeneous DNA pattern had a significantly higher frequency of lymph node metastasis than did those with the homogeneous DNA pattern (P < 0.05).

CONCLUSIONS

For evaluation of the highly malignant potential of esophageal carcinoma by nuclear DNA contents, it is important to identify accurately intratumoral heterogeneity. Because different DNA stem lines were evident in different areas of the lesion, evaluation of multiple specimens from a wide area of each lesion is needed to determine with accuracy the degree of intratumor DNA stem line heterogeneity.

DNA mapping of colorectal neoplasms: a flow cytometric study of DNA abnormalities and proliferation

BACKGROUND

There is some evidence that neoplastic development and progression evolve through a multistep process associated with hyperproliferation and genetic alterations. Therefore, changes of proliferation and of cellular DNA content within the adenoma-carcinoma sequence were studied.

METHODS

Using a "mapping" procedure, 12 adenomas and 18 carcinomas were analyzed flow cytometrically and histologically. In addition, normal mucosa adjacent to and distant from the tumors was assessed in the same way.

RESULTS

Of 59 adenomatous fractions, 35.6% (n = 21) were aneuploid, whereas the incidence of aneuploidy was 63.5% (54/85) in the carcinomatous sites. Additional tetraploidies were identified in 5 (8.5%) and 13 (15.3%) adenomatous and carcinomatous samples, respectively. Cell proliferation, as determined by the percentage of S-phase cells, was significantly (P < 0.001) higher in the carcinomatous specimens (14.8% +/- 0.8%; mean +/- SEM) than in the adenomatous ones (8.1% +/- 0.7%). It decreased to normal mucosa adjacent to (5.1% +/- 0.5%) and distant (5.3% +/- 0.6%) from the neoplasms. DNA mapping of the tumors revealed both distinct regions and extended areas of aneuploidy and tetraploidy. There is evidence from the mapping data that aneuploid populations arise at a single focus of the adenoma and expand over large areas before a subpopulation of cells acquires the capacity of invasion.

CONCLUSIONS

These data showing consecutive DNA content abnormalities within the colorectal adenoma-carcinoma sequence provide support for genomic instability and clonal evolution as important events of tumorigenesis and progression.

DNA heterogeneity in prostatic adenocarcinoma. A DNA flow cytometric mapping study with whole organ sections of prostate

BACKGROUND

The degree of DNA heterogeneity varies between tumors arising at different sites. The presence of a significant degree of variability within a given tumor may result in problems in the interpretation of DNA flow cytometric findings. This study evaluated the degree of DNA heterogeneity in prostatic adenocarcinoma.

METHODS

A total of 122 3-mm punch biopsy specimens were evaluated from single representative whole organ sections from nine cases of prostate cancer (range, 4-18 samples per case; mean, 12 samples; median, 14 samples). Individual punch biopsy specimens were graded and reviewed to confirm the presence of carcinoma and processed for DNA ploidy analysis.

RESULTS

Assessable histograms, defined as having a coefficient of variation of the diploid G0/G1 peak of 7.5% or less, were available for 111 (91%) of the samples. Of the nine cases studied, five (56%) showed heterogeneity in the DNA pattern (diploid plus aneuploid, n = 1; diploid plus tetraploid, n = 2; and diploid plus tetraploid plus aneuploid, n = 2). All four cases having a homogeneous DNA content were DNA diploid in all samples. In those cases with a heterogeneous pattern, the areas having abnormal DNA patterns could not be predicted by histologic pattern or grade.

CONCLUSIONS

From this study, the authors conclude that a significant degree of DNA heterogeneity exists within individual cases of prostatic adenocarcinoma, and this may be an important confounding factor in DNA ploidy studies.

Heterogeneity in early and advanced gastric carcinomas by flow cytometric DNA analysis

We investigated 230 systematically sampled fresh specimens from 12 early and 26 advanced gastric cancer patients by DNA flow cytometry for heterogeneity in DNA content. Fifty-eight percent of the 12 early gastric cancers were uniformly diploid and 42% were uniformly aneuploid. Fifty-four percent of advanced cancers were uniformly diploid in superficial layers and 42% were uniformly diploid in deep layers, whereas 46% were uniformly aneuploid in superficial layers, and 50% were uniformly aneuploid and 8% were heterogeneously aneuploid and diploid in deep layers. Both diploid and aneuploid samples were obtained from 15% for advanced cancers, but ploidy heterogeneity did not occur in early cancers. Heterogeneity for DNA index (more than one aneuploid DNA index) occurred in 46% of whole thickness of advanced cancers, in 19% of superficial layers of advanced cancers, and in 8% of early cancers. We concluded that DNA ploidy determination using superficial layer specimens may be reliable in early gastric cancer but must be interpreted with care in advanced cancer.

High levels of DNA index heterogeneity in advanced breast carcinomas. Evidence for DNA ploidy differences between lymphatic and hematogenous metastases

BACKGROUND

The aim of this study was to investigate DNA ploidy status and DNA index heterogeneity of lymphatic and hematogenous metastases of advanced breast carcinomas and the relations among the various tumor sites.

METHODS

DNA ploidy status was analyzed by flow cytometry on frozen and paraffin-embedded tissue blocks taken from primary and metastatic tumor sites in 18 patients with advanced breast cancer.

RESULTS

Presumably because of the extensive sampling, high percentages of DNA aneuploidy, DNA multiploidy, and DNA index heterogeneity were found in primary breast carcinomas as well as in lymph node and distant metastases. DNA aneuploid tumor stemlines were frequently accompanied by DNA diploid tumor stemlines. Most of the DNA tumor stemlines found in the primary tumors recurred in lymph node (55%) and distant (59%) metastases, even after 17 years of relapse-free survival. DNA tumor stemlines found in distant metastases, however, often differed from those in lymph node metastases (61%).

CONCLUSIONS

A marked DNA index heterogeneity can be found in primary and metastatic tumor sites when appropriate sampling is applied. There were no DNA ploidy subclasses, notably absent in either type of metastasis, indicating similar metastatic capacities of both DNA aneuploid and DNA diploid tumor stemlines in advanced breast carcinomas. The difference in DNA ploidy status between lymphatic and hematogenous metastases suggest that these metastases can be generated independently.

Mucin-producing pancreatic tumors: a study of nuclear DNA content by flow cytometry

Nuclear DNA content in eight surgically resected mucin-producing pancreatic tumors (MPPT) consisting of two mucinous intraductal adenocarcinomas (MIDAC), two mucinous intraductal adenomas (MIDA), one mucinous cyst-adenocarcinoma (MCAC), and three mucinous cystadenomas (MCA) were measured by flow cytometry using paraffin-embedded tissue samples. The technique of Shutte was used for the preparation of paraffin-embedded tissue into single dissociated nuclei, while the method of Vindelov was used for staining the isolated nuclei with propidium iodine. Clinicopathologically, the four patients with MIDAC or MIDA were all male and had cystic lesions with a dilated pancreatic duct at the head of the pancreas, while the four patients with MCAC or MCA were all females and had cystic tumors at either the body or tail of the pancreas. All eight patients with MPPT had no metastasis to the regional lymph nodes and were all still alive without recurrence. In an analysis of nuclear DNA content, seven of eight patients had DNA diploid tumors while one patient with a MIDAC perforating the duodenum and choledochus had a DNA aneuploid tumor. Thus, these findings suggest that DNA diploid patterns in MPPT might be associated with a favorable prognosis in MPPT although some patients whose MPPT invaded the surrounding organs might have DNA aneuploid tumors.

Quality control study of the Italian group of cytometry on flow cytometry cellular DNA content measurements

A quality control study on DNA flow cytometry, extended to 43 national laboratories, has been carried out by the Italian Group of Cytometry, using defined fixed suspensions of cultured human leukemia K562 cells and human blood lymphocytes. The participating laboratories were allowed to follow their own staining and measurement protocols. Aliquots of cellular suspension had to be measured three times on the same day and two other times on different days. A large heterogeneity of procedures emerged among participants. The average of mean DNA index laboratory values, from 36 laboratories who sent evaluable data, was 1.68, with a range from 1.49 to 1.97. The coefficients of variation ranged from 2.35 to 9.39% and from 2.79 to 8.5% for diploid and aneuploid peaks, respectively. Statistical analysis of the results showed quite good intralaboratory reproducibility, but statistically significant differences were observed among laboratories, for both DNA indices and coefficients of variation. These differences appear to be consistent. For standardization, it is essential that efforts should be made to identify the main sources of variation and to control them.

Correlation of DNA ploidy, histopathology, stage and clinical outcome in gastric carcinoma

The determination of nuclear DNA ploidy from paraffin-embedded specimens was performed by flow cytophotometry on 277 surgically resected primary gastric carcinomas to assess the relationship of various pathological findings and DNA content with survival. The preparation of samples was performed by a modification of Hedley's technique and the staining method of Vindelov. Eighty-nine (32%) carcinomas were DNA diploid, 69 (25%) were DNA tetraploid, and 119 (43%) were DNA aneuploid. DNA non-diploid patterns were significantly associated with macroscopic ulcerative appearance, location of the tumour in the proximal stomach, histological grade, and advanced stage of tumour. Patients with DNA non-diploid cancers, and specifically DNA aneuploid cancers, exhibited significantly poorer survival than patients with DNA diploid tumours. These data support the prognostic value of tumour DNA content in patients with resected gastric carcinoma.

The succinate dehydrogenase inhibition test for evaluating biopsy specimens and resected tumors of advanced gastric cancer

An in vitro chemosensitivity study of both biopsy specimens and surgically resected tumors of advanced gastric cancer from 12 patients was evaluated using the succinate dehydrogenase inhibition (SDI) test. A decrease in succinate dehydrogenase (SD) activity as an indicator of chemosensitivity was determined using cisplatin (CDDP), etoposide (VP-16), and mitomycin C (MMC). In this study, 29 of a total 36 experiments were evaluable (80.6%) and significant correlations were found in all three of the antitumor drugs (P < 0.03). This finding suggests that the SDI test using biopsy specimens may prove valuable for assessing the preoperative chemosensitivity of advanced gastric cancer.

One or multiple samplings for flow cytometric DNA analyses in breast cancer-prognostic implications?

Flow cytometric assessments of DNA ploidy status and the S-phase fraction (SPF) have been shown to yield prognostic information in breast cancer. The aim of the present investigation was to elucidate the reproducibility of results with regard to tumor DNA heterogeneity, and to ascertain whether the prognostic value of DNA measurements might be enhanced by analyzing two pieces of a tumor instead of one. Agreement with regard to ploidy status (diploid versus non-diploid) was obtained in 90% of cases (71/79) when two adjacent sections of the tumor were investigated, and in 77% of cases (10/13) when four biopsies from different quadrants of the tumor specimen were investigated. The corresponding figures for agreement in SPF (divided into three categories, less than 7.0%, 7.0-11.9%, and greater than or equal to 12%) were 75% (59/79; 2-sample series) and 55% (7/13; 4-biopsy series). The main reason for variance in ploidy results was the difficulties in distinguishing near diploid cell populations. Discrepancies in SPF categories could be explained by minor fluctuations in SPF values near the cut-off levels, or by variance in ploidy status, the fraction of non-diploid nuclei, and background noise due to cell debris. There was a stepwise increase in recurrence rate (RR) among patients with increasing SPF category (RR: 20%, 41%, and 53%). Patients whose SPF categories varied, from low or intermediate in one part of the tumor to high in another, seemed to have a poor prognosis (RR = 57%).(ABSTRACT TRUNCATED AT 250 WORDS)

Flow-cytometric DNA content analysis of esophageal squamous cell carcinomas

To better understand the mechanisms of esophageal carcinogenesis, abnormalities in DNA content of esophageal squamous cell carcinomas were studied. Cellular DNA content was determined by flow cytometric study of 70 endoscopic biopsy specimens obtained from 26 patients with esophageal squamous carcinoma. High-quality histograms were obtained for 23 patients. Twenty-one patients had at least one aneuploid population in their tumor. In 7 patients, multiple aneuploid peaks were detected. Specimens from 2 patients were diploid. The interpretation of the DNA histograms was difficult in 3 patients; an aneuploid population of cells was probable in 2 of them. A statistically significant relationship was found between the degree of differentiation and DNA content abnormalities in the regions of the tumors that could be evaluated by endoscopic biopsies: well-differentiated carcinomas had diploid or small aneuploid populations containing less than 15% of the cells, whereas DNA histograms of moderately or poorly differentiated carcinomas were characterized by large aneuploid peaks representing 25%-90% of the cells and a higher proliferative fraction. No relationship was found between the size or the stage of the tumor and the DNA content detected in endoscopic biopsy samples. The frequency and the multiplicity of abnormal clones in esophageal squamous carcinomas indicates that this cancer, like esophageal adenocarcinoma, develops an association with an acquired genomic instability that produces abnormal clones of cells, according to the multistep model of neoplastic progression.

Distribution of aneuploid cell populations in ulcerative colitis with dysplasia or cancer

Flow cytometry was used to detect the presence and assess the distribution of aneuploid cell populations in eight proctocolectomy specimens from patients with ulcerative colitis. Mucosal samples were taken according to a systematic protocol for flow cytometry, the surrounding tissue was examined histologically, and the distributions of flow cytometric and histologic abnormalities were "mapped" within each resected colon. Two resection specimens that were negative for dysplasia lacked aneuploid cell populations. Four resection specimens with final case diagnoses of dysplasia or Dukes' stage A carcinoma had 1-5 regions of aneuploidy or increased 4N (G2/tetraploid) cell populations located in discrete areas of the colon. Two specimens with dysplasia or Dukes' stage C carcinoma each had 14-15 different, often overlapping, regions of aneuploidy or increased 4N (G2/tetraploid) cell populations involving large portions of the colonic mucosa. Analysis of the DNA content of the invasive portion of the tumor from the specimen with a Dukes' stage C carcinoma showed a single aneuploid cell population. The results show that single or multiple aneuploid cell populations are often present in colons resected for ulcerative colitis with dysplasia or early cancer. The distribution of these aneuploid cell populations suggests that each represents a clone of cells that has expanded to occupy a discrete region of colonic mucosa. Additional genetic errors may result in multiple aneuploid cell populations that may be associated with an increased risk of developing cancer. These data, therefore, are consistent with the hypothesis that genomic instability and clonal evolution are associated with the progression to dysplasia and carcinoma in ulcerative colitis. Because flow cytometry can measure aneuploid cell populations in colonoscopic mucosal biopsies, it may prove to be complementary to histology for detecting patients with ulcerative colitis who are at risk for neoplastic progression.

DNA-ploidy and survival in gastric carcinomas: a flow-cytometric study

In 125 gastric carcinomas the nuclear DNA content was determined by flow cytometry from formalin-fixed and paraffin-embedded tissue of surgical specimens. The carcinomas were of intestinal or mixed type (85), and diffuse type (40). DNA-aneuploidy was found in 46% of the intestinal type and in 42% of the mixed type, but only in 15% of the diffuse-type carcinomas (P less than 0.01). The total rate of DNA-aneuploidy was 34%. Carcinomas localized in the cardia were more frequently DNA-aneuploid than tumours in other localizations (P less than 0.01). DNA-aneuploid carcinomas had metastasized more frequently to regional lymph nodes (P less than 0.05) whereas no correlations with tumour stage and cytological/histological grade were detected. In 94 patients follow-up data were available. DNA-aneuploidy was associated with a statistically significant poorer prognosis when compared to DNA-diploid tumours only in advanced gastric carcinomas with lymph node metastases (P = 0.0488) and in the subgroup of advanced intestinal and mixed-type tumours (P = 0.0289).

Pre-operative nutritional support and tumour cell kinetics in malnourished patients with gastric cancer

Stimulation of tumour growth by intensive exogenous nutrient administration could be a major clinical problem when nutritional support is provided in malnourished cancer patients. Nutritional repletion has been clearly shown to stimulate tumour growth in animal models but not in humans. The purpose of this prospective study was to evaluate the effect of pre-operative nutritional support on the proliferative characteristics of gastric tumour cells evaluated by 3H-thymidine (3HT) incorporation and flow cytometry (FCM). Thirty-three malnourished patients with advanced gastric cancer were allocated randomly into two groups receiving different types of nutritional support during the interval between endoscopy and operation: parenteral and/or enteral hyperalimentation (Group 1), and oral alimentation as possible or peripheral fluids (Group 2). In 16 patients with diploid tumours the percentage of 3HT labelled cells and of cells in S+G(2)M phase did not differ between the multiple samples taken from the mucosal surface of the neoplasia. Tumour samples showed higher mean values of cycling cells than the surrounding normal tissue. Both methods (3HT - FCM) demonstrate that tumour cell proliferation is not enhanced following a prolonged period of pre-operative artificial nutrition.

Flow cytometric analysis of DNA stemline heterogeneity in primary and metastatic breast cancer

Flow cytometric DNA-ploidy analysis was used to investigate intratumor DNA stemline heterogeneity in primary breast carcinomas and lymph node metastases (LNM). The study was done in tumor specimens from 44 patients 35 of whom had LNM. In all, measurements were done in 214 different samples of primary tumors and 211 lymph nodes. Sixty-one percent (27/44) of the primary tumors were found to have multiple DNA aneuploid stemlines when the data of the separate samples per tumor (mean 4.9) were compared. Only five of 44 (11%) primary tumors were DNA diploid; two of these had DNA aneuploid metastases. Statistical analysis of these results indicated that, on average, four samples are needed for reliable determination of the DNA ploidy status of primary tumors by flow cytometry. In the majority of the cases (26/35), distinct tumor DNA stemlines found in LNM were also present in the primary tumor, which suggests that the generation of DNA ploidy diversity may have taken place prior to metastasis. Multiploidy was not related to tumor size but, particularly for LNM, was significantly correlated with age (r = 0.40, P = 0.02). The results of this study support the view that breast cancer is an extremely heterogeneous disease and that underestimation of this factor might account for the disagreement in literature about the prognostic value of DNA ploidy determinations.

Variability in DNA measurements in multiple tumor samples of human colonic carcinoma

The DNA ploidy and cell-cycle distribution of three separate fresh tissue samples of 60 colorectal adenocarcinomas were analyzed by flow cytometry. DNA ploidy was concordant among the three samples in 38 cases (63.3%). In the remaining 22 cases (36.6%), the DNA histograms of two of the three multiple samples were similar; however, the ploidy of the third sample was discordant. No relationship was observed between Dukes' stage and histologic grade with concordance or discordance among samples. Thus, in about one third of the colonic carcinomas, a single sample showing either a diploid or diploid-cycling DNA histogram would not detect aneuploid DNA patterns. Comparison of scrapes and fine-needle aspirates of tumors as alternative sampling methods of tumors for DNA ploidy analysis indicated a strong association with the tumor ploidy (84% and 96%, respectively) only when the ploidy of the multiple samples was concordant. In about 25% of the cases, tumor scrapes and fine-needle aspirates did not correlate with the "most abnormal" ploidy observed in one of the three tissue samples. The data suggest that single or even double tissue samples may not show aneuploid DNA patterns in a substantial proportion of colorectal cancers.