Flow cytometry as a tool for the prognostic assessment of human neoplasia

FT-IR spectroscopy: a powerful tool in pharmacology

In the present work we report a Fourier Transform Infrared (FT-IR) analysis performed on rat encephalon samples in the CH-OH vibrational stretching region (2400-3800) cm(-1), in order to reveal the presence of a very diffuse commercial benzodiazepine: VALIUM. The comparison between the spectral features of normal brain and the ones of samples with administrated substance has unambiguously showed that the CH stretching region seems not to suffer from any change for the pharmacological treatment, instead the OH band is strongly modified probably due to the presence of a new spectral contribution characteristic of diazepam molecule.

Colorectal cell kinetics

The assessment of cell proliferation in colorectal tissue may provide information with both prognostic and therapeutic implications. A variety of methods are available, including flow cytometric estimations of S phase fraction, immunohistochemical and autoradiographic visualization of exogenous and endogenous proliferation proteins, and morphological and stathmokinetic techniques. There is some correlation between Dukes stage and proliferation state features, and there is increased proliferative activity throughout the adenoma-carcinoma sequence. Data on cell proliferation rates are difficult to obtain. When correctly applied, the metaphase arrest technique remains the 'gold standard' of measuring proliferation, but its usefulness in clinical practice is limited. Recent studies have employed dual measurement flow cytometry and double labelling techniques to produce rate data.

The relation of radiosensitivity of hypopharyngeal squamous cell carcinoma to DNA ploidy

PURPOSE

The purpose of this study was to examine the radiosensitivity of T1, N0, M0 squamous cell carcinomas of the hypopharynx treated solely with external beam radiation.

MATERIALS AND METHODS

Nuclear DNA content and cell cycle kinetics of 29 archival paraffin-embedded specimens suitable for interpretation were analyzed with an ELITE flow cytometer (Coulter Diagnostics, Opa Locka, FL).

RESULTS

In the radiosensitive group with no evidence of disease for 36 months, 86% of the tumors were diploid and 14% were aneuploid. The mean DNA index for this group was 1.02. In the radioresistant group, with recurrence within 36 months, 80% of the tumors were aneuploid, and 20% were diploid. The mean DNA index for this group was 1.32.

CONCLUSIONS

The findings could have clinical significance because if aneuploidy occurs in an early hypopharyngeal squamous cell carcinoma, the clinician might select surgical resection over radiation therapy.

Prognostic significance of DNA content in bladder cancer based on flow cytometric analysis of 249 transitional cell carcinomas

The prognostic significance of DNA index (DI), S-phase fraction, and heterogeneity determined by flow cytometric DNA analysis was assessed in a prospective study of 249 newly diagnosed transitional cell carcinomas of the bladder. The median observation time was 4.8 years. A total of 456 subpopulations were detected. The S-phases could be estimated in 299 subpopulations. A DI > 1.25 or an S-phase above 9.7% were strongly correlated to invasiveness. One hundred and ten patients were treated with transurethral resection (TUR). Relapse-free survival could not be predicted by the DNA-derived parameters. Univariate analysis of survival showed prognostic significance of diploidy (0.98 < DI < or = 1.02, P = 0.02), hypotetraploidy (1.50 < DI < or = 1.96, P = 0.002), and S-phase size (P = 0.008). Multivariate analysis pointed to the T-classification (RR = 1.64) and hypotetraploidy (RR = 1.57) as prognostic parameters for survival of TUR-treated patients. One hundred and thirty-nine patients received radiotherapy (RT). A significantly better response was found for tumors with a subpopulation with a hypertetraploid DNA content (DI > 2.04, P = 0.05), and a significantly worse response for subpopulations with a maximum S-phase > 24.5% (P = 0.04). T-classification and histological grade had no predictive value. A logistic regression analysis indicated an estimated probability of response to RT of 77% for tumors with a DI > 2.04 and an S-phase < 24.5%, whereas tumors with a DI < 2.04 and an S-phase > 24.5% had only a 28% probability of response. The poor response to RT, predicted by an S-phase > 24.5%, translated into a poor survival, whereas the better treatment response found for patients with a DI > 2.04 did not result in a longer survival. Multivariate analysis pointed to S-phase (RR = 1.70), T-classification (RR = 1.60), and grade (RR = 0.65) as independent prognostic parameters for survival of RT-treated patients.

Flow cytometric DNA analysis of classic and steroid-induced Kaposi's sarcoma

Flow cytometric DNA analysis of various tumours has indicated a correlation between the degree of malignancy and ploidy; results which could have clinical significance. We analysed the ploidy of Kaposi's sarcoma (KS) tumours, and classified the results according to clinical history and histological findings. We found that patients on steroid treatment had an aneuploid pattern, and most of the patients with classic-type KS had a diploid pattern on flow cytometry.

Deoxyribonucleic acid flow cytometric study in pheochromocytomas and its correlation with clinical parameters

OBJECTIVES

To study deoxyribonucleic acid flow cytometry (DNA-FC) in pheochromocytomas and its correlation with clinical parameters.

METHODS

Fifty cases of pheochromocytomas of a total of 58 cases were studied for DNA-FC from archival paraffin-embedded tissue blocks and were correlated with clinical parameters (ie, size of tumor, benign or malignant pathologic type, vanillymandelic acid [VMA] level in 24 hour urine, age, sex, duration of symptoms, symptom scores).

RESULTS

A total of 19 cases were diploid while 31 cases (62%) showed DNA aneuploidy with 21 cases tetraploid. Four cases were malignant. All of them were tetraploid. However, among the 46 benign cases, 10 were aneuploid and 17 were tetraploid. All 19 cases with DNA diploidy were benign. The DNA-FC did not correlate with other clinical parameters in our study.

CONCLUSIONS

We confirmed a high incidence of DNA aneuploidy in pheochromocytomas. All malignant pheochromocytomas were tetraploid and all cases with DNA diploidy were benign. Long-term follow-up of all cases, especially those with DNA aneuploidy (including tetraploidy), is mandatory.

Flow cytometric analysis of squamous cell carcinoma of the tongue

The purpose of this study was to examine the relationship between anatomic location and the cytogenetic and cytokinetic characteristics of squamous cell carcinoma of the tongue to determine the diagnostic and prognostic potential of flow cytometry. Fifty-two archival, paraffin-embedded specimens of squamous cell carcinoma of the tongue in clinical stages I-IV acquired from 1975 to the present were analyzed with an ELITE flow cytometer (Coulter Diagnostics, Opa Locka, FL). Histopathologic grading was performed by the same pathologist based on tumor differentiation. Of the 40 specimens found suitable for analysis, several correlations were noted. First, as the clinical stage increased, the % S-phase increased. Second, there was no correlation between the histologic grade and the % S-phase. Finally, the % S-phase was higher in those tumors with nodal involvement.

The relevance of flow-cytometric DNA content in the evaluation of lung cancer

Cells from a group of 185 patients suffering from malignant tumours (160 non-small-cell lung carcinoma, 13 small-cell lung carcinoma, and 12 non-epithelial tumours) and 6 with benign lung tumours were studied by flow cytometry in order to detect the prognostic value of DNA content. A total of 144 (90%) non-small-cell lung carcinomas (NSCLC) and 8 (62%) small-cell lung carcinomas (SCLC) exhibited aneuploidy. Furthermore 52% (83 patients) NSCLC, 24% (3 patients) SCLC and 50% (6 patients) non-epithelial tumours demonstrated multiclonality. Benign cases showed diploid DNA content. For actuarial survival analysis using the Bergesson and Gage method and the Greenwood variance, 142 patients were selected. Statistical comparisons were made by the use of the t-test for unpaired data between fixed times. No correlation was observed between ploidy and stage, histological grading or treatment modality. A statistically significantly better survival was observed after 12, 18 and 24 months of follow-up for diploid and monoclonal (with the exclusion of hypo- and hypertetraploid) patients. Thus, flow-cytometric DNA analysis may be useful in prognostic assessment of human lung tumours.

Tissue markers of potentially malignant human oral epithelial lesions

Tissue markers of potential malignancy have been sought for many years. Cell surface markers, particularly blood group and histocompatibility antigens, have shown great promise and several squamous carcinoma antigens have been identified--but not fully studied in potentially malignant lesions. Growth factors and receptors also need further study. Cytoplasmic markers of potential malignancy have been examined and, of these, keratins, filaggrin, and some carcinoma antigens show most promise. Nuclear analyses have promise but are time-consuming and expensive. Image cytometric analyses appear to be sensitive and predictive: oncogene and tumour suppressor analyses remain to be fully evaluated. New investigative techniques at the cellular and molecular level show increasing promise at defining potentially malignant oral epithelial lesions but more prospective studies are required.

Cell-cycle and ploidy analysis in bone marrow and liver cells of rats after long-term consumption of irradiated wheat

Rats were fed for 4 or 90 days either with 70% freshly irradiated wheat (0.25, 0.75 or 2.25 kGy) and 30% complementary feed or with a control diet. None of the parameters examined (food consumption, body weight, haematological analysis, histopathological inspection of thymus, lung, liver, spleen and kidney, DNA analysis of bone marrow cells and nuclei from liver cells by flow cytometry) showed any statistically significant association with the feeding regimen. Minor changes in ploidy of liver cells and cell cycling of bone marrow cells were detectable (wheat-irradiation dose-dependent increase in G2/M-phase bone marrow cells up to 0.6%, decrease of 8C nuclei up to 1.1% in liver cells). From the pattern of alterations observed in our study, radiolytic by-products of wheat irradiation with a spindle poison-like activity can be excluded. Polyploid cells do not accumulate within the 90-day feeding period. The minor effects on cell cycle and ploidy observed are qualitatively comparable with the effects seen after food restriction in animal studies. It is suggested that an altered composition of fatty acids (the components of wheat most sensitive to irradiation) is responsible for these marginal effects. Our findings may explain the earlier findings of Bhaskaram and Sadasivan (American Journal of Clinical Nutrition 1975, 28, 130-135) who reported an increase in the number of polyploid cells in the lymphocytes of malnourished children fed irradiated wheat. The most likely mechanisms for such an effect are adaptive, constitutively regulated processes, similar to those which respond to food restriction. It is concluded that the consumption of irradiated wheat does not, therefore, pose any health risk to humans.

Methodological Analysis of Flowcytometric Measurements of Nuclear Dna in Oncology

The application of specific and proven guidelines is required for flow cytometric nuclear DNA analysis, which can provide precise information on genomic quantitative modifications and the proliferative activity of tumour tissues, clinically useful for prognosis and monitoring of therapy and recurrencies. The authors review the various protocol phases to be followed for a correct analysis and discuss the main problems that can be encountered in the procedural steps and in interpreting the histograms.

Flow cytometric analysis of posterior oropharyngeal tumors

To date, few studies have evaluated the diagnostic and prognostic potential of flow cytometry in oropharyngeal tumors. The purpose of this study was to evaluate the interrelationship of anatomic location with the cytogenetic and cytokinetic characteristics of squamous cell carcinomas of the posterior oropharynx. Forty-eight paraffin-embedded squamous cell carcinoma specimens from the posterior oropharynx in clinical stages I to IV were analyzed with an Epics-C flow cytometer (Coulter Diagnostics, Hialeah, FL). Histopathologic grading was performed by the same pathologist, based on tumor differentiation. Of the 38 specimens suitable for analysis, several correlations were noted. First, as the %S-phase increased, the clinical stage increased. Second, as the histologic grade increased, the aneuploid frequency increased. Finally, as the tumor size increased, the histologic grade increased. From the results of this study, it was concluded that %S-phase may be useful in assessing the prognosis of squamous cell carcinomas of the posterior oropharynx. DNA index or aneuploid frequency, also may have value as a prognostic indicator. Finally, the lack of correlation between TNM staging and histologic grading stems not from tumor size but from nodal and metastatic involvement. Further studies are warranted to better define the usefulness of flow cytometric analysis in squamous cell carcinomas of the oropharyngeal region.

Flow cytometric evaluation of ovarian cancer

BACKGROUND

Despite recent advances in the treatment of ovarian cancer, the long-term prognosis for patients with this malignancy appears to depend more on tumor prognostic factors than on treatment regimens. The traditionally used prognostic factors are often subjective and, currently, have not been sufficient to determine individual patient prognosis.

METHODS

Newer techniques of quantitative cytologic testing, including flow cytometry, facilitate the objective evaluation of tumor cell heterogeneity and the identification of additional prognostic factors.

RESULTS

There is good evidence, mainly from retrospective studies, that DNA ploidy is a valuable prognostic indicator in patients with both early-stage and late-stage ovarian cancer. Most of the recent flow cytometric studies have identified ploidy as an independent prognostic factor, with aneuploidy predicting a significantly shorter survival time, even in patients with borderline malignant tumors. Flow cytometric determination of cell cycle information (e.g., S-phase fraction or proliferative index) may represent additional prognostic information and may be used to predict the early tumor response to treatment.

CONCLUSIONS

Although additional prospective studies are needed to establish the exact value of flow cytometric evaluation for ovarian cancer and other gynecologic malignancies, there is little doubt that the prognostic value of this information will influence clinical management of patients with these malignancies in the near future.

Prediction of recurrence in pituitary tumours: a flow cytometric study using in vivo bromodeoxyuridine

Although most pituitary tumours are regarded as benign, there is a significant risk of local recurrence and a few are frankly malignant. The prediction of clinically aggressive behaviour by histopathological means is inadequate and the selection of patients for postoperative radiotherapy has often been empirical. The flow cytometric analysis of the DNA content of certain intracranial tumours has suggested a correlation between a high proliferative index and a tendency to recur. The in vivo administration of bromodeoxyuridine (BUdR) yields a reliable and accurate S-phase labelling index and evaluation by flow cytometry allows a much greater and therefore more representative number of cells to be examined. We report our results for the flow cytometric evaluation of the S-phase fraction in a group of 11 human pituitary tumours following the preoperative administration of BUdR and discuss the correlation between high values of S-phase fraction and clinically aggressive behaviour. Initial results suggest a correlation between radiological evidence of tumour invasion and an S-phase greater than 2%.

The relation between the results of cytophotometric examination of endometrial carcinoma and clinical course of these disease

We made a prospective cytophotometric study of 48 cases of endometrial carcinoma. Thirty-two (66.7%) of the cases had diploid DNA content and the proportion of non-diploid tumors increased with the staging of tumors, lack of differentiation and depth of myometrial invasion. DNA content (AE), DNA malignancy grade (DNA-MG) and 5c exceeding rate were statistically significant in relation to the clinical course of the disease and the histological grade of differentiation. DNA parameters appear to be especially suitable for the objective assessment of malignancy.

Flow sorting of tumor cells for morphometric analysis, particularly of rare cells

Using flow cytometric DNA measurement and sorting combined with morphometric light microscopy, different groups of cells were studied in a human melanoma pleural effusion, a human melanoma lymph node metastasis and a mouse tumor, as well as in normal reference tissues. Beside cells of the predominant tumor cell population, three types of rare tumor cells were studied after enrichment by sorting: a) giant cells from the greater than 8c region, comprising about 5% of the tumor cells, b) binucleated and multinucleated cells with unequal nuclear sizes within the same cell, found at frequencies of about 1.5%, and c) less than 2c cells which were derived from the so-called "debris"-region of the DNA histogram, found at frequencies of about 1 to 6%. All these rare cells were found only in the malignant tumors and not in the benign reference tissues. Morphometry showed that the increase in the cellular DNA content in the different fractions of tumor cells was combined with an increase in the cellular and nuclear sizes. However, the n/c-ratio was constant in the whole range of tumor cell fractions, including the fractions from the the less than 2c and the greater than 8c regions. The n/c-ratio of the less than 2c cells and giant cells differed from that of corresponding normal cells underlining their origin from the predominant tumor cell population. The possible linkage between the occurrence of the three rare cell types and genetic instability of tumors related to faulty nucleus and cell division is discussed.

Cellular heterogeneity of DNA/total-protein content in human lung tumors, as determined by flow cytometry

With the aim of distinguishing neoplastic cell sub-populations of different prognostic and diagnostic significance, dual-parameter measurements (DNA/protein) have been simultaneously determined in a (256, 256) channel matrix in lung samples derived from 110 patients affected by neoplastic and non-neoplastic lung diseases. Biparametric analysis demonstrated that cells with abnormally high red fluorescence (i.e., protein content), which is indicative of unbalanced growth, were often observed in malignant tumors as compared with normal lung samples. Furthermore, the dual-parameter analysis allowed recognition of additional aneuploid tumor-cell lines, indicating that the frequency of cytometrically determined diploid tumor is lower than that previously described by DNA monoparametric analysis. The recognition of aneuploid subpopulations by dual-parameter analysis in clinically and histologically negative one-parameter flow-cytometric "diploid" samples assumes important diagnostic value. The results have also shown the presence of multiple protein sub-populations in clones with the same ploidy value, indicating a higher level of cellular heterogeneity than demonstrated by DNA monoparametric measurements.

Prediction of relapse or survival after resection in human hepatomas by DNA flow cytometry

To investigate the change of DNA content and the effect of synthetic phase (S-phase) fraction on hepatocytes and hepatomas, DNA content and S-phase fraction were measured by flow cytometry in human livers and hepatoma tissues. The ploidy status of nontumor parts of resected hepatoma, fetal liver, and focal nodular hyperplasia were diploid, similar to that of the normal liver. Three patterns of DNA ploidy in human hepatoma cells were newly classified, namely, pattern I, diploid tumors; pattern II, aneuploid tumors with single G0/G1 peak; and pattern III, aneuploid tumors with more than one G0/G1 peaks. Among the 130 resectable hepatomas measured for DNA ploidy status, 84 (64.6%) were pattern I, 20 (15.4%) pattern II, and 26 (20%) pattern III. Multivariate analyses for those 130 patients who underwent hepatic resection showed that, in addition to tumor size, DNA ploidy was another prognostic factor in predicting overall survival and disease-free survival. Patients with small tumors (less than 5 cm) had a significantly higher overall survival rate than those with large tumor (greater than 5 cm). Patients with pattern III hepatomas had a significantly lower overall survival rate and a higher recurrent rate than did those with pattern I or pattern II tumors. The S-phase fraction was a significant predictor of overall survival rate in patients with pattern II, but not with pattern I, tumors. We conclude that DNA flow-cytometric measurements of ploidy and S-phase fraction are potential important prognostic predictors in patients with resectable hepatomas.

Analysis of ascites from patients with ovarian carcinoma by cell flow cytometry

Cell flow cytometry offers the opportunity to analyze cytopathological samples with regards to DNA content and proliferative activity. To investigate whether this modality can quantitate certain aspects of ovarian carcinoma by analyzing ascites, 43 samples from patients with advanced papillary serous adenocarcinoma of the ovary were studied. In 28 samples (65%) ploidy and the percentage of cells in S phase (%S phase) could be analyzed. Fifteen samples could not be analyzed because of overlapping cell populations distorting distinct cell cycle phases. Of the 28 samples studied, 8 (29%) were diploid and 20 (71%) were aneuploid. The DNA in aneuploid samples ranged from 1.23 to 2.65. The %S phase for aneuploid was greater than that for diploid samples. Patients with diploid samples survived longer. Cytometric analysis of cells from ascites in 4 patients in whom disease progressed after they received chemotherapy showed that the percentage of cells in S phase increased. Cells from ascites established in vitro showed that ploidy and proliferative activity changed as cells were passed in culture. In conclusion, the analysis of ascites by cell flow cytometry may be a prognosticator in patients with advanced ovarian carcinoma. In addition, conclusions extrapolated from in vitro data to the in vivo situation should be done cautiously since late-passaged cells may not always be representative of the initial tumor sample.

Patterns of DNA-ploidy in operable colorectal carcinoma: a prospective study of 100 cases

A prospective study of cellular DNA content was made by means of flow cytometry in a nonconsecutive series of 100 patients undergoing surgery for primary colorectal adenocarcinoma. DNA-aneuploidy was present in 80% of cases (80/100); 39% of these were multiclonal (31/80). There was no significant correlation between DNA-ploidy and the clinical and pathological features examined, except for the primary tumor site (right colon vs. left colon vs. rectum: P less than 0.001). After a minimum follow-up of 30 months, out of 40 patients with no local invasion and/or distant metastases, 100% (9/9) of those with DNA-diploid neoplasias showed no signs of disease relapse, vs. 55% (17/31) of the DNA-aneuploid cases (P less than 0.05). Furthermore, in 45 cases with a minimum follow-up of 30 months, overall survival was 90% in patients with DNA-diploid carcinomas and 43% in the DNA-aneuploid cases (P less than 0.05).

New insights into the causes of cancer

Recent advances in molecular biologic analysis have led to major new insights concerning the genetic mechanisms underlying the development of cancer. This article examines the current state of our understanding of the genetic basis underlying the possible mechanisms of carcinogenesis and metastasis. The nature of the genetic lesions found in some cancer-causing genes, cancer-inhibiting genes, growth factor genes, and metastasis genes is discussed, as is the impact that these may have on clinical oncology.

Flow cytometric DNA ploidy analysis of squamous cell carcinoma of the oral cavity. Comparison with clinical staging and histologic grading

The clonal DNA content of tumor biopsy specimens of 110 patients with primary and untreated squamous cell carcinoma of the oral cavity was determined by flow cytometric study. The ploidy status was compared with tumor size and histologic grading. Thirty tumors (27.3%) were diploid; in 80 cases (72.7%) cell lines with abnormal DNA content were detected. The portion of aneuploid tumors increased with decreasing degree of histologic differentiation (P less than 0.001) from G1 (38.1%) to G2 (76.6%) and G3 (92.0%). Only one of 13 T1 carcinomas (7.6%) showed abnormal clonal DNA content, but 76.9% of T2 and 90.6% T3 tumors (P less than 0.001) did. The emergence of aneuploid clones obviously represents a marker of malignancy progression in oral carcinoma.

Cytokinetic investigation of lung tumors using the anti-bromodeoxyuridine (BUdR) monoclonal antibody method: comparison with DNA flow cytometric data

In order to investigate the cytokinetics of malignant tumors and non-malignant lesions of the lung, tissue samples from 57 patients affected by non-small-cell carcinoma (NSCLC), small-cell carcinoma (SCLC), and benign and inflammatory lesions have been analyzed using the BUdR monoclonal antibody (MAb) method. This method is based on the preparation, at the time of surgery, of viable monocellular suspensions (using collagenase and DNase treatment) and the concomitant administration of BudR. The percentage of BudR-labelled cells was monitored by fluorescent microscopy using an FITC-labelled second antibody. In NSCLC, each histological group showed a wide range of labelling index (LI) values. On the contrary, SCLC exhibited a more homogeneous kinetic behaviour as evidenced by a narrowly distributed, higher LI. Tumors shown to be diploid by flow cytometry did not show a lower LI than aneuploid tumors. Furthermore, differences were constantly observed between the S-phase percent calculated using BUdR and that calculated using the DNA flow cytometric (FC) histogram, the latter always showing higher S-phase values. In an attempt to study the intra-tumor proliferative heterogeneity, multiple-site sampling was performed. Proliferative heterogeneity seemed to be higher inter-tumor than intra-tumor. Finally, a positive correlation (p less than 0.05) was found between LI and the actual doubling time (DT) of the primary tumor mass, evaluated using sequential radiographs. In conclusion, the present BUdR method can be considered a useful source of relevant information on in vivo cell growth, in parallel to other clinical (DT) and biological (DNA content) approaches.

Prognostic implications of DNA ploidy in squamous cell carcinomas of the tongue assessed by flow cytometry

A total of 47 primary squamous cell carcinomas of the tongue were analysed by DNA flow cytometry. With respect to their clonal DNA content two distinct tumor groups could be distinguished. In 14 cases the tumors (29.8%) were dipoid, whereas in 33 cases (70.2%) additional cell lines characterized by abnormal DNA content could be detected. A significant increase of aneuploid cases with tumor size as well as with decreasing histological differentiation could be detected. Aneuploid cell lines are lacking in T1 as well as in most G1 carcinomas but predominate in T3 and G3. Furthermore, cervical lymph node involvement was recognized in the majority of aneuploid primary carcinomas (81.8%) but was largely lacking in diploid tumors (21.4%). Hence, the presence of aneuploid cell lines is clearly connected with clinical and histopathological parameters, each of which have turned out to worsen the prognosis in tongue carcinomas.

Significance and therapeutic implications of tumor regression following radiotherapy in patients treated for squamous cell carcinoma of the oropharynx and pharyngolarynx

The prognostic significance of tumor regression following radiotherapy was evaluated in 1,897 patients with oro- and pharyngolaryngeal cancer. Complete tumor regression occurred in 62% and 80% at the end of treatment and 2 months later, respectively. Complete regression was significantly higher for early tumors than for advanced stages and for exophytic lesions compared to deeply infiltrative cancers. Depending on tumor location, 75% to 90% of T1, T2 stages and 50% to 80% of more advanced tumors were locally controlled in patients who experienced complete tumor regression at 2 months. The local failure rate was at least 80% for those who did not have complete regression. The local failure rate for the incomplete responder was the same for early and advanced tumors. Complete tumor clearance following radiotherapy is a reliable indicator of permanent local control. Tumor regression after a dose of 5,000 to 5,500 cGy should be used as a guide to select patients who could be treated by either radical irradiation or surgery.

A review of techniques and results obtained in one laboratory by an integrated system of methods designed for routine clinical flow cytometric DNA analysis

Establishing flow cytometric DNA analysis as a clinical routine procedure requires adequate and proven guidelines, by which the data can be obtained and interpreted to directly influence management of the individual patient with a specific neoplasm. The present paper is intended as a contribution to such guidelines, of which only fragments are available today. We have previously described a system of methods, designed for routine flow cytometric DNA analysis. In the present status report our experience, based on approximately 18,000 samples (clinical and experimental) is summarised. Sample acquisition with fine-needle aspiration, storage at -80 degrees C, internal standardization by chicken (CRBC) and trout red blood cells (TRBC), staining with propidium iodide (PI), and analysis in the flow cytometer is recapitulated, with emphasis on previously unpublished aspects. The method of statistical analysis which has an integrating role is described in some detail. A lack of linearity between channel number and DNA content was determined experimentally, and the coefficient of variation (CV) was found to decrease with increasing channel number. The corrections in the algorithm of deconvolution made necessary by these findings are fundamental for estimating the end results. The zero point adjustment and procedures for changing from one batch of standards to another are described. A systematic approach to interpretation of DNA histograms is attempted and illustrated by data from clinical specimens of malignant lymphoma, breast cancer, small cell lung cancer, cancer of the oral cavity, and bladder cancer. Some problems are still unsolved and visual inspection is required to determine if the quality of the individual histogram is satisfactory. Inspection of the fluorescence/light scatter dot-plot provides additional information for the recognition of artifacts. The results stress that good quality DNA histograms with as small CVs as possible are important for interpretation of the data. It is essential that statistical methods are employed to extract the key end-point results. These are the number of subpopulations and their relative representation, and for each subpopulation the DNA index (DI) and the fractions of cells in the cell cycle phases. For the DNA data to have any rationally based impact on clinical decision making, it must be demonstrated that they have an independent prognostic value. Strategies for final evaluation are discussed. Multicenter trials on fresh material, to accrue quickly the number of patients necessary for firm conclusions, are suggested.

DNA flow cytometric studies of 66 human lung tumors analyzed before treatment. Prognostic implications

To investigate the prognostic implications of DNA flow cytometry in human lung tumors, we analyzed specimens from patients with neoplastic and non-neoplastic lung disease. Most non-neoplastic and normal (taken at the resection border) lung samples yielded a single cell population with diploid DNA content (only two normal lung specimens from two cancer patients had aneuploid DNA content). At least one aneuploid cell subpopulation was seen in 91 percent of NSCLC and 50 percent on SCLC. To show intratumor heterogeneity, multiple-site sampling was done whenever possible in both primary tumor and metastatic sites, revealing a high incidence of multiclonality (50 percent). Although diploid tumors were rare, they associated with a higher survival rate than aneuploid monoclonal and multiclonal tumors with hypoploid and/or hypertetraploid clones, which had the lowest survival. Cellular DNA content analysis in patients with lung tumors may be useful in prognostic evaluation.

DNA distribution pattern in chronic gastritis. I. DNA ploidy and cell cycle distribution

DNA distribution patterns were flow cytometrically recorded in gastric biopsy specimens from patients with chronic gastritis (CG) and chronic atrophic gastritis (CAG). DNA aneuploidy was found in 3 of 58 patients with CG and in 7 of 82 patients with CAG. Cell cycle analysis disclosed significantly higher percentages of cells in S-phase and G2M-phase, respectively, in CAG than in CG. With regard to the proliferative activity the total CAG group could be partially differentiated by the degree of severity. CAG with total atrophy showed significantly higher percentages of cells in S-phase than CAG with mild and moderate atrophy. CAG without dysplasia showed lower percentages of cells in S-phase and G2M-phase than CAG with severe dysplasia (p greater than 0.05). The occurrence of intestinal metaplasia was correlated to a significantly higher percentage of cells in G2M-phase.

Flow cytometry using paraffin-embedded tissue: five years on

The use of paraffin-embedded tissue for flow cytometry is reviewed. A number of technical modifications of the original 1983 method have been described, aimed at improving the accuracy of DNA measurements by minimizing cell debris or reducing coefficients of variation, and at simplifying sample preparation. Over 100 clinical studies have now been reported, mainly assessing the effect of DNA index on prognosis, and those published up until mid-1988 are summarized in an appendix. More recently there have been developments in the use of monoclonal antibodies to measure oncogene products or proliferation markers in addition to DNA content. Detailed clinical evaluation and standardization of these more sophisticated methods is still some way ahead, but as was the case with DNA index, the use of archival material from patients whose outcome is already known should speed this process.

Cell proliferation kinetics in human solid tumors: relation to probability of metastatic dissemination and long-term survival

A large number of studies have investigated the relationship between the long-term survival and the percentage of tumor cells in S phase assessed by autoradiography after tritiated thymidine labelling, image cytometry, flow cytometry or labelling with an halogenated analog of thymidine, in various types of human solid tumors. The survey of the results clearly shows that the S-phase fraction (SPF) is of high prognostic significance in several types of cancers, in particular in breast cancers, non-Hodgkin lymphomas, ovarian cancers, neuroblastoma, bladder cancers and lung cancers. SPF was found of high independent significance in 10 of the 11 studies in which multivariate analyses of prognostic factors had been carried out. Proliferation appears generally to be of higher prognostic significance than ploidy. In view of the wide differences in the biological characteristics of the tumors studied, it is likely that the association between a high proliferation rate and the degree of tumor aggressiveness is a general feature of human solid tumors. However, high proliferative rate of tumor cells is probably not the cause of tumor biological aggressiveness but a variable associated with it. The extent to which cells escape from the regulatory systems which control their proliferation appears to be a good index of tumor progression.

Association of near-diploid DNA content and N-myc amplification in neuroblastomas

Seventeen neuroblastomas at different clinical stages were analysed for their N-myc copy number and flow cytometrically determined DNA content. Aneuploidy was found in 11 patients (65 per cent), whereas the remaining were near-diploid. N-myc amplification was found significantly (P less than 0.05) confined to near-diploid tumors (3 out of 6 cases). This finding indicates a very selective mechanism of oncogene amplification which is independent of gross chromosomal imbalance and limited to specific loci in the human genome. Association of near-diploidy and age at diagnosis older than 24 months was also demonstrated (P less than 0.05). Thus, flow cytometric analysis of DNA content together with N-myc gene dosage allowed us to distinguish two different subsets of neuroblastoma tumors: the first one aneuploid, with single-copy N-myc, usually observed in patients younger than 24 months with localized or IV-S clinical stages; the second one near-diploid, with frequent N-myc amplification, usually observed in patients older than 24 months with advanced clinical stages.

Competitive exclusion of clonal subpopulations in heterogeneous tumours after stromal injury

Xenografted artificial heterogeneous tumours (AHTs) were created by admixing, in a ratio of 9:1 or 1:9, two clonal subpopulations (designated as clones A and D) obtained from a heterogeneous human colon adenocarcinoma. In unperturbed AHTs these percentages remain constant with increasing tumour size. At average volumes of 250 mm3, AHTs were X-irradiated (15 Gy) and changes in growth rate and composition assayed. A and D cells exhibited equivalent levels of survival after in vivo irradiation as determined by excision assay procedures. At about 2-3 weeks post-irradiation AHTs exhibited a significant enrichment of the majority population in both the 1:9 or 9:1 A:D AHTs. Additional studies were concomitantly performed to determine whether these changes were mostly a function of normal tissue damage or of parenchymal tumour cell killing. In these studies, the normal tissue only was irradiated, tumour cells were implanted one day after irradiation, and the composition of AHTs assayed as a function of time post-irradiation. In these studies, similar shifts in composition with similar kinetics to that seen in the in situ irradiations were found. We therefore propose that these compositional shifts are mainly a reflection of radiation damage to the stromal microenvironment, which is consequently unable to support tumour growth adequately leading to competitive exclusion of the minority subpopulation.

Cellular heterogeneity in human epithelial neoplasms

Tumor cell heterogeneity has in recent years been the subject of numerous excellent review articles, but comprehensive reviews may not always distinguish between that which is known about tumors from direct observation and that which is inferred from the study of analagous systems. The purpose of this review is to describe what is known about cellular heterogeneity in human tumors and to discuss current models of the pathogenesis of cellular heterogeneity in light of the evidence available from the study of human cancer.

Flow cytometric DNA analysis of medulloblastoma. Prognostic implication of aneuploidy

Paraffin-embedded surgical specimens from 26 infants and children with medulloblastomas treated between 1972 and 1981 were examined for DNA ploidy by flow cytometry (FCM). All patients received a standard treatment (a combination of maximum debulking of medulloblastoma and postoperative craniospinal irradiation with a posterior fossa boost of 5000 rad or more). They were studied to correlate the results of the findings of FCM DNA analysis with their final outcome, DNA ploidy, and extent of tumor resection. All seven patients with totally resected aneuploid medulloblastoma are alive, whereas only one of six patients with subtotally resected diploid medulloblastoma is alive (P = 0.0047). The current study suggests both DNA ploidy and extent of surgical resection are the most important determinant of patients' prognosis. Patients in selected group, particularly those with subtotally resected diploid tumor, are advised to undergo aggressive adjuvant chemotherapy.

Prognostic significance of DNA index, multiploidy, and S-phase fraction in ovarian cancer

Paraffin-embedded tumor samples from 157 ovarian cancer patients were analyzed by DNA flow cytometry. Tumor ploidy had prognostic significance in both early and advanced ovarian cancer. After adjusting for stage, residual tumor mass, histopathologic type, treatment, and age of patient in a Cox regression analysis, the relative risk of death was two-fold higher in single DNA-aneuploid and sixfold higher in DNA-multiploid tumors as compared to DNA-diploid tumors (P less than 0.0001). A tetraploid DNA index was associated with a relatively low risk ratio, whereas hypertetraploid tumors were highly malignant. S-phase fraction (SPF) had prognostic value especially in DNA-diploid tumors. The simultaneous evaluation of DNA index, the number of aneuploid cell clones, and SPF gave more prognostic information than the determination of tumor ploidy alone. On the basis of these parameters we have developed a classification of tumor DNA histograms for better prognostic assessment of ovarian cancer.

Prognostic significance of flow cytometry in lung cancer. A 5-year study

Flow cytometrically determined cellular DNA content has been measured on specimens from 101 patients affected by lung cancer (40 epidermoid cell carcinoma, 22 adenocarcinoma, 21 large cell carcinoma, 11 small cell carcinoma, and seven undifferentiated carcinoma), and one by mesothelioma. Ninety-eight of 102 (96%) patients with neoplastic disease evidenced the occurrence of at least one cytometrically aneuploid cell subpopulation. Fifty-five of 102 (54%) cases evidenced the occurrence of multiclonality, that is, the presence of more than one aneuploid stem cell line. However, the incidence of multiclonality in lung carcinoma was statistically different in surgical cases (where multiple site sampling from the primary and lymph nodes was possible) in comparison to the nonsurgical ones (e.g., bronchial washing): 48/77 (62%) and six of 24 (25%), respectively. Therefore, only the 77 surgical patients were used for further analysis. The cases were classified according to the DNA index (DI) in the following way: Group A (tumors with one or more stem lines with DI ranging from 1 to 2) and Group B (tumors with at least one stem line with DI less than 1 or greater than 2). A significant correlation has been found between the cytometric ploidy condition so defined (Groups A and B) and the tumor mass doubling time (DT), Group B being associated with fast growing tumors (DT lower than 90 days). A statistically better 12-month survival rate (5-year maximum follow-up) was observed in Group A (88%) in respect to Group B (47%) and is evident in the patient survival time course. A better prognostic indication can be achieved by stratifying the patients according to both the cytometric ploidy condition and the tumor DT. Flow cytometric data can usefully contribute to the prognostic assessment of lung carcinoma provided that representative cellular material is collected by multiple site sampling.

Influence of systematic errors on the evaluation of the S phase portions from DNA distributions of solid tumors as shown for 328 breast carcinomas

The portion of cells in S phase has proved to be a valuable prognostic indicator of early relapse and life expectancy, particularly in breast carcinoma. Comparisons of published data on samples of primary breast carcinoma biopsies showed that the values obtained by analyses of flow cytometric DNA distributions were generally higher than those of determinations based on the tritiated thymidine (3H-ThdR) labeling index (LI). Flow cytometric DNA analyses of 328 biopsy samples of primary breast carcinomas revealed that these differences could be explained by varying contributions of debris background. Since this influence is inversely proportional to the cell counts in each channel, it may cause considerable errors, particularly in the S phase channels, which normally contain the lowest counts of the DNA distributions. Two different mathematical rationales were tested in order to separate DNA distributions from the debris superimposition. No appreciable differences were found with respect to the essential results. After appropriate subtraction of the background levels, the previously reported discrepancies between cytometrically determined S phase portions and 3H-ThdR LI values disappeared, and good agreement was achieved for the comparable tumor samples of the present study. In conclusion, debris background subtractions should generally precede the DNA histogram analyses, particularly of solid tumors, in order to obtain reliable S phase values.