Predictive value of regression rates following chemotherapy of small cell carcinoma of the lung.

Tumor volumes measured at the time of initial therapy, during the 28 days following treatment, and following subsequent courses of therapy for 29 patients with small cell carcinoma of the lung were determined from serially measurable roentgenographic lesions. Tumor-halving times were calculated following initial therapy, and the proportions of pretreatment tumor volumes were evaluated within 28 days after initial therapy for 26 patients. Pretreatment tumor volumes ranged from 22.5 to 485 cu cm, with a median of 87 cu cm, a log mean of 83 cu cm, and a linear mean of 113 cu cm. The tumor-halving times ranged from 4 to 86 days, with a median of 12 days, a log mean of 12 days, and a linear mean of 16 days. The reduction of tumor volume expressed as a proportion of pretreatment volume following therapy ranged between 0.02 and 0.65, with a median value of 0.22, a log mean of 0.18, and a linear mean of 0.26. Using the linear mean of 0.26 as a discriminant for survival analysis, patients with less than 0.26 had a median duration of survival of 12 months, which was significantly longer (p = 0.035) than the median survival of 8 months for patients with greater than 0.26. Tumor-halving time of 16 days was also able to separate the survival durations of 12 months of those less than 16 days compared to 8 months for greater than 16 days (p = 0.0429). Tumor regression rate, determined from two consecutive tumor volume measurements, was correlated with the tumor volume (r = 0.677; p less than 0.0001); and volume dependency of the tumor regression rate, as specified in Gompertzian kinetics, was demonstrated.

Carcinoembryonic antigen for monitoring patients with small cell carcinoma of the lung during treatment.

Carcinoembryonic antigen (CEA) was measured at specific intervals in the plasma of 56 patients with small cell carcinoma of the lung. Of these patients, 47 had serial analyses for varying periods during their illness, 42 had pretreatment CEA levels, and 17 of the latter patients had determinations throughout the entire course of their disease. Pretreatment CEA levels were elevated above 2.5 ng/ml for 74% of the 42 patients and above 5.0 ng/ml for 48%. Although exceptions were noted, in general, a direct relationship was found between pretreatment CEA levels and extent of disease or tumor burden. Initial stage of disease, however, was more predictive of survival than was the pretreatment CEA level. With response to therapy, a corresponding decrease in CEA levels occurred for patients with an elevated pretreatment level. For those patients with a pretreatment CEA level below 5.0 ng/ml, an immediate slight increase in level was often seen associated with response and followed by a subsequent fall after one month. A rising CEA level was usually found with recurrence or progression of disease after initial response and occurred frequently prior to clinical evidence of progression. In combination with careful clinical evaluation, serial CEA measurements can aid in assessing tumor changes associated with treatment in patients with small cell carcinoma of the lung particularly at the times of recurrence or disease progression following a partial or complete response.

The discrete-time kinetic model analysis of DNA content distributions in experimental tumour cells.

A method was developed to analyse and characterize FMF measurements of DNA content distribution, utilizing the discrete time kinetic (DTK) model for cell kinetics analysis. The DTK model determines the time sequence of the cell age distribution during the proliferation of a tumor cell population and simulates the distribution pattern of the DNA content of cells in each age compartment of the cell cycle. The cells in one age compartment are distributed and spread into several compartments of the DNA content distribution to allow for different rates of DNA synthesis and instrument dispersion effects. It is assumed that the DNA content of cells in each age compartment has a Gaussian distribution. Thus, for a given cell age distribution the DNA content distribution depends on two parameters of the cells in each age compartment: the average DNA content and its coefficient of variation. As the DTK model generates the best fit DNA content distribution to the FMF measurement data, it enables one to estimate specific values of these two parameters in each stage of the cell cycle and to determine the fraction of cells in each cycle phase. The method was utilized to fit FMf measurements of DNA content distributions and to analyse their relationship tothe cell kinetic parameters, namely cell loss rate, cell cycle times and grwoth graction of exponentially growing Chinese hamster ovary cells in vitro and, also, with a wide range of coeffficients of variation, of the L1210 ascites tumour during the growth period.

Quantitative analysis of biological marker synthesis in tumor cell cycle.

A quantitative relationship between tumor cell number and biologic marker concentration has been investigated and characterized by the previously developed discrete-time kinetic model for the study of cell kinetics. Here, this model is further expanded to cope with both cell cycle kinetics and biologic marker synthesis. A synchronized tumor-cell population is examined to determine the time course of the synthesis of markers in relation to cell cycle. The DNA content distributions, measured by flow microfluorometry, are analyzed by use of the model, and the cell age distribution is extracted. The average marker content per cell in cell cycle is measured for each time sequence in synchronized cell populations. The model, incorporating the cell age distribution and the average marker content per cell in cell cycle, enables one to generate the marker content distribution, from which the cell number is estimated from the marker concentration. The model performance is further evaluated with Chinese hamster ovary cells, and their polyamine content and the total polyamine concentration during synchronization is calculated and related to the total cell number.

Kinetic analysis of cell size and DNA content distributions during tumor cell proliferation: Ehrlich ascites tumor study.

In order to study the growth dynamics of proliferating and non-proliferating cells utilizing discrete-time state equations, the cell cycle was divided into a finite number of age compartments. In analysing tumor growth, the kinetic parameters associated with a retardation in the growth rate of tumors were characterized by computer simulation in which the simulated results of the growth curve, the growth fraction, and the mean generation time were adjusted to fit the experimental data. The cell age distibution during the period of growth was obtained and by a linear transformation of the state transition matrices, was employed to specify the cell size and DNA content distributions. In an application of the model, the time-course behavior of cell cycle parameters of Ehrlich ascites tumor is illustrated, and the parameters important for the transition of cells in the proliferating compartment to the non-proliferating compartment are discussed, particularly in relation to the G1-G0 and G2-G0 transitions of non-cycling cells as revealed by the variation of cell size distribution.

Analysis of the effects of antitumor drugs on cell cycle kinetics.

A cell cycle stage-specific multicompartmental model has been developed and used to investigate the effects of antitumor drugs on the proliferation of tumors. The drug effects simultaneously considered are (a) non-cycle-specific killing and cycle stage-specific killing of cells, (b) progression delay of cells through the cell cycle phases which may bring about an accumulation of cells in various phases of the cell cycle, and (c) prolongation of cell cycle times. These effects are analyzed in terms of possible variations in the behavior of cell kinetic parameters (namely, cell cycle times, cell loss rate, and growth fraction) and are implemented in the model specifying proper functional forms for the parameters. The time-course of drug distribution in a tumor-host system is also described by a two-compartment model and the factors affecting drug action are quantitatively formulated as a function of drug concentration. Simulation is carried out to examine the effects of BCNU, cytosine arabinoside, and methotrexate on the cell cycle and proliferation kinetics of L1210 leukemia, and the results of the simulation compare favorably with available experimental data. Also discussed are the sensitivity of drug effects to variation in dosage schedule and the different nodes of drug actions exerted on each cell cycle phase.

Variation of cell kinetic parameters in relation to the growth rate of the Ehrlich ascites tumor.

A multicompartmental model of the cell cycle and proliferation kinetics was used to analyse the time-course behavior of the cell cycle time, the growth fraction, and the cell loss rate during Ehrlich ascites tumor growth. The growth rate of Ehrlich ascites tumor cells as the tumor aged was significantly influenced by change in the cell cycle time.

Analysis of the proliferation kinetics of Burkitt's lymphoma cells.

The in vitro proliferation kinetics of a cell line derived from a patient with American Burkitt's lymphoma were investigated at three different growth phases: lag (day 1), exponential (day 3) and plateau (day 5). The growth curve, labeling and mitotic indices, percentage labeled mitosis (PLM) curves and DNA content distributions were determined. The data obtained have been analysed by the previously developed discrete-time kinetic (DTK) model by which a time course of DNA distributions during a 10-day growth period was characterized in terms of other cell kinetic parameters. The mean cell cycle times, initially estimated from PLM curves on days 1, 3 and 5, were further analysed by the DTK model of DNA distributions and subsequently the mean cell cycle times with respect to DNA distributions during the entire growth period were determined. The doubling times were 39.6, 31.2 and 67.2 hr, respectively, at days 1, 3 and 5. The mean cell cycle time increased from 23.0 to 37.7 hr from day 3 to day 5 mainly due to an elongation of the G1 and G2 phases. A slight increase in the cell loss rate from 0.0077 to 0.0081 fraction/hr was accompanied by a decrease in the cell production rate from 0.0299 to 0.0184 fraction/hr. This calculated cell loss rate correlated significantly with the number of dead cells determined by trypan blue exclusion. Analysis of the number of dead cells in relation to the cell cycle stage revealed that a majority of cell death occurred in G1 (r + 0.908; P < 0.0001). There was a good correlation between the in vitro proliferation kinetics at plateau phase of this Burkitt's lymphoma derived cell line and the in vivo proliferation kinetics of African Burkitt's lymphoma (Iversen et al., 1974), suggesting the potential utility of information obtained by in vitro kinetic studies.

Cyclization characteristics of cyclodextrin glucanotransferase are conferred by the NH2-terminal region of the enzyme.

Cyclodextrin glucanotransferase (CGTase; EC 2.4.1.19) is produced mainly by Bacillus strains. CGTase from Bacillus macerans IFO3490 produces alpha-cyclodextrin as the major hydrolysis product from starch, whereas thermostable CGTase from Bacillus stearothermophilus NO2 produces alpha- and beta-cyclodextrins. To analyze the cyclization characteristics of CGTase, we cloned different types of CGTase genes and constructed chimeric genes. CGTase genes from these two strains were cloned in Bacillus subtilis NA-1 by using pTB523 as a vector plasmid, and their nucleotide sequences were determined. Three CGTase genes (cgt-1, cgt-5, and cgt-232) were isolated from B. stearothermophilus NO2. Nucleotide sequence analysis revealed that the three CGTase genes have different nucleotide sequences encoding the same amino acid sequence. Base substitutions were found at the third letter of five codons among the three genes. Each open reading frame was composed of 2,133 bases, encoding 711 amino acids containing 31 amino acids as a signal sequence. The molecular weight of the mature enzyme was estimated to be 75,374. The CGTase gene (cgtM) of B. macerans IFO3490 was composed of 2,142 bases, encoding 714 amino acids containing 27 residues as a signal sequence. The molecular weight of the mature enzyme was estimated to be 74,008. The sequence determined in this work was quite different from that reported previously by other workers. From data on the three-dimensional structure of a CGTase, seven kinds of chimeric CGTase genes were constructed by using cgt-1 from B. stearothermophilus NO2 and cgtM from B. macerans IFO3490. We examined the characteristics of these chimeric enzymes on cyclodextrin production and thermostability. It was found that the cyclization reaction was conferred by the NH2-terminal region of CGTase and that the thermostability of some chimeric enzymes was lower than that of the parental CGTases.

A quantitative approach to determining disease response during therapy using multiple biologic markers: application to carcinoma of the breast.

This analytical study was undertaken in an effort to develop a model for a quantitative approach to the evaluation of multiple biological marker levels in blood and urine as a means for determining tumor changes during treatment of patients with malignant disease. The potential biologic markers measured in patients with carcinoma of the breast consist of three urinary polyamines (putrescine, spermidine and spermine), three urinary nucleosides (pseudouridine, N2, N2-dimethylguanosine and 1-methylinosine), and plasma carcinoembryonic antigen (CEA). The distribution patterns of the seven markers measured pretreatment and five weeks after initiating therapy were examined by grouping the patients into the three categories of progression, stable, or regression based on their clinical response to treatment. In addition to the individual marker measurements, the pretreatment and posttreatment values of the ratios of the polyamine levels (spermine/putrescine, spermine/spermidine, and spermidine/putrescine) and the nucleoside levels (N2, N2-dimethylguanosine/pseudouridine, 1-methylinosine/pseudouridine, and 1-methylinosine/N2, N2-dimethylguanosine) were also evaluated. In the pretreatment measurements, CEA levels were elevated for 76% of the patients and the three nucleosides were elevated for 36% of the patients and the three nucleosides were elevated for 36% to 37% of the patients. Urinary spermidine and spermine levels were abnormal for 27% and 24%, respectively, while putrescine levels were elevated for 7% of the patients. When all 14 marker measurements and the 12 ratios of these measurements were considered, the multiple regression equation evaluated the treatment results with a multiple correlation coefficient (R = 0.891; P less than 0.100) about 2.4 times higher than with the most sensitive single marker variable, N2, N2-dimethylguanosine/pseudouridine (R = 0.377; P less than 0.05), alone. Stepwise regression analysis revealed that the minimum number of multiple marker measurements and their ratios required to achieve the maximum value of the multiple correlation coefficient (R = 0.653; p = 0.010) was fifteen. These include the pre and posttreatment measurements of CEA, spermine, N2, N2-dimethylguanosine and 1-methylinosine, as well as two ratios of the polyamines and three ratios of the nucleosides in the post-treatment of the polyamines and three ratios of the nucleosides in the post-treatment measurements. These data suggest that the utilization of regression analysis to evaluate the monitoring utility of multiple marker measurements may be of clinical value.

Serum protein-bound carbohydrates and small cell carcinoma of the lung. Correlations with extent of disease, tumor burden, survival, and clinical response categories.

The levels for serum protein bound neutral carbohydrates (fucose, mannose, and galactose) were determined at specific intervals for 40 patients with small cell carcinoma of the lung and compared to the corresponding carcinoembryonic antigen (CEA) levels. In pretreatment samples, the frequency of elevation was 92.5% for fucose and 77.5% each for mannose and for galactose. CEA determined in these same samples was elevated (greater than 5 ng/ml) in 45.0%. One or more of the three carbohydrate levels were elevated in pretreatment serum of 95.0% of the patients. The individual frequency of elevation for each carbohydrate was significantly related to initial stage of disease (P less than 0.01). Median survival was significantly longer for patients based on a discriminant of less than 3 carbohydrates elevated in pretreatment samples (25 months) to all 3 elevated (11 months) with P = 0.0302. A single value, termed the biomarker index, was calculated to represent the summation of the individual carbohydrate levels per individual serum sample. The biomarker index was found to be directly correlated with extent of primary disease, number of metastic sites, tumor burden, and clinical response categories assessed at serial time points. For patients with both low Biomarker Index values and normal CEA levels in pretreatment samples, an initial rise in both determinations occurred frequently corresponding to partial or complete tumor response. The occurrence of such discordant results must be considered as a likely possibility for those patients with low or normal pretreatment biological marker levels and subsequent response to primary chemotherapy.

Urinary polyamines for evaluating the course of disease for patients with small cell carcinoma of the lung.

Clinical correlates with urinary excretion of polyamines were evaluated for 29 newly diagnosed and 35 previously treated patients with small cell carcinoma of the lung (SCC). The frequencies of pretreatment abnormalities were 12 (41%) for putrescine, 18 (62%) for spermidine, and 20 (69%) for spermine. In assessing disease parameters, the combined use of the abnormalities of spermidine and spermine as a discriminant was more effective than that of all three polyamines; it correlated significantly with extent of limited and extensive disease (P less than 0.001), and also resulted in significant separation of survival curves, the median survival of 11 months for both elevated compared to 19 months for neither or only one elevated (P = 0.062). No significant difference was seen in the abnormalities between no metastasis and one metastasis, whereas the frequencies of the abnormalities was highly increased in two or more metastases. The distribution of polyamines determined at regular treatment intervals showed distinctively more elevated patterns in progressive disease than in stable disease or partial and complete responses (P less than 0.01). In order to evaluate therapeutic effects on the relationship between polyamine excretion and tumor regression, correlations between urinary putrescine and spermidine were determined. The values of the ratio of spermidine to putrescine were significantly smaller in responders than in nonresponders (P less than 0.01); and these may be related to smaller tumor mass and higher tumor proliferative activity in responders, and larger tumor mass and lower tumor proliferative activity in nonresponders.

Multiple biological markers and breast carcinoma: a preliminary study in the detection of recurrent disease after primary therapy.

The use of a selected group of biological markers in breast cancer patients who are disease free but at risk of relapse after mastectomy has potential for detecting recurrent tumor before there is clinical evidence. In this preliminary study, multiple materials were serially analyzed in the body fluids of patients without overt tumor but receiving adjuvant chemotherapy because of positive axillary nodes at surgery. The total frequency of elevated levels was determined and compared for those patients who remained disease free, for those who subsequently relapsed, and for a third group of patients with proven metastases. Frequency of elevation was directly proportional to increasing disease. Although differences in the relative frequency of individual materials was observed, the same trends with increasing tumor burden were found. The results suggest that the serial measurement of biological markers has potential for indicating the presence of occult disease. A nucleus of biological markers to be considered should include carcinoembryonic antigen, urinary hydroxyproline/creatinine ratio for bone lesions, and gamma-glutamyltranspeptidase for liver involvement.

Multiple biologic markers in the monitoring of treatment for patients with small cell carcinoma of the lung: the use of serial levels of plasma CEA and serum carbohydrates.

The monitoring utility of serial patterns of a single marker (carcinoembryonic antigen) level and multiple marker (three carbohydrates-fucose, mannose and galactose) levels in patients with small cell carcinoma of the lung was investigated using a quantitative approach. A serial multiple regression (SMR) model was formulated to assess the disease response following the first to the tenth course of therapy and resulted in the multiple correlations ranging from 0.183 (NS)-0.706 (P less than 0.005) for CEA, and 0.502 (P less than 0.250)-0.760 (P less than 0.025) for three carbohydrates, respectively. The appraisal of these markers utilizing the SMR model points out that: (1) the serial levels of CEA greater than 5.0 ng/ml are significantly correlated with the disease course whereas the serial levels less than 5.0 ng/ml reflect the trend of variation in the disease course, but with less accuracy; and (2) the levels of three carbohydrates, any one elevated before and during therapy, are significantly correlated with the disease course.

A feasibility study in the development of biological markers for ovarian cancer.

As a primary feasibility study for the selection of biomarkers for more extended clinical evaluation, 17 potential biomarker candidates were measured in the body fluids of patients with ovarian carcinoma. For comparative purposes, patients were staged and separated into three groups: those considered completely free of disease, those with residual but minimal tumor, and those with advanced disease. Individual markers included plasma carcinoembryonic antigen, serum human chorionic gonadotrophin, urinary beta-aminoisobutyric acid, serum UDP-galactosyltransferase, and urinary hydroxyproline. Structurally related groups of biomarkers included six modified nucleosides and three polyamines analyzed in urine, and three serum protein-bound neutral carbohydrates. The respective chromatographic methods developed for these latter biochemical materials enabled all the individual compounds in each group to be quantitated simultaneously in one analytical run. The general frequency and degree of elevation for the total number of biomarkers was directly proportional to increasing tumor burden with specific exceptions, human chorionic gonadotropin and beta-aminoisobutyric acid. Galactosyltransferase was the most frequently elevated in the limited disease categories. Several of the biomarkers were elevated in the majority of patients with advanced disease and appeared potentially superior to carcinoembryonic antigen or human chorionic gonadotrophin.

Modified ribonucleosides as biological markers for patients with small cell carcinoma of the lung.

A variety of individual modified ribonucleosides may be elevated in the urine of cancer patients. They can be readily measured quantitatively in a single reversed-phase high-performance liquid chromatographic run. A total of 41 patients with small cell carcinoma of the lung were studied. For 5-ribonucleosides determined in the pretreatment urine of 28 patients, the respective frequency of elevation was directly related to stage of disease. One or more nucleosides were evaluated in the pretreatment urine of 27 out of 28 patients (96%). Included were 11 patients with limited disease and 10 (91%) had 2 or less than 2 nucleosides elevated, whereas 16 out of 17 (94%) with extensive disease had 3 or more elevated. Based on this same discriminant, median survival was significantly extended for patients with 2 or less nucleosides elevated (24 months) in contrast to 3 or more (10 months). Using a single number to represent the summation of equally weighted individual nucleoside values as a composite score, a direct relationship was found between increasing extent of disease or tumor burden. This was in contrast to more variable results for carcinoembryonic antigen analyzed in plasma samples obtained at the same time. When determined serially the composite score paralleled in general the clinical response categories for individual patients.