DNA-SYNTHESIS AND PLOIDY IN NON-HODGKINS-LYMPHOMAS DEMONSTRATE INTRAPATIENT VARIATION DEPENDING ON CIRCADIAN STAGE OF CELL SAMPLING

Significant circadian cell cycle variations with a maximal number of c ells in S-phase during the night have been found in a series of 24 pat ients (18 men and 6 women) with histologically established non-Hodgkin 's lymphomas. Pathological lymph nodes of a total of 26 patients were punctured and aspirated by fine needle technique every 4 h during a si ngle 24-h time span. Twenty-four patients (92.3%) had Stage III or IV disease. Twelve patients (46.1%) had low, grade, 10 patients (38.5%) h ad intermediate grade. and 4 patients (15.4%) had high grade lymphomas according to the Working Formulation. The samples were analyzed b flo w cytometry, and DNA synthesis (S-phase) and ploidy were determined ac cording to circadian stage. The individual mean 24-h S-phase varied fr om 2.2 +/- 1.2% mean +/- SD) to 24.0 +/- 3.3%. Within the group of pat ients with low grade lymphomas, a wide range in mean S-phase from 2.4 +/- 1.2% to 9.2 +/- 2.8% was observed. The percentage variation within each patient between the lowest and highest S-phase as compared to th e lowest value (range of change) during the 24-h time span varied from 21 to 353%, with a mean range of change of 128 +/- 19%. When each ind ividual S-phase series was converted to percent of mean and combined f or analysis by one-way analysis of variance to test for time-effect ac ross 2 12-h time spans (8 p.m.-8 a.m. versus 8 a.m.-8 p.m.), S-phase v ariation according to circadian stage was found to be statistically si gnificant (P < 0.004), with higher values found in the 8 p.m.-8 a.m. t ime span. By single cosinor analysis, S-phase yielded a near significa nt P value of 0.069 for the least-squares fit of a 24-h cosine to all data as percent of mean, with the acrophase found to be near midnight (0.05 h). For those patients with low and intermediate grade lymphomas and with mean S-phase values < 10.0%, we found that mean S-phase was higher during winter (5.8 +/- 0.4%) than during spring (3.8 +/- 0.3%) or during fall (3.6 +/- 0.3%) (P < 0.001, analysis of variance). Twent y-one of the 26 patients (80.8%) had an aneuploid, hypodiploid, or nea r diploid population in one or several of the repeated samples. For th e whole series, the DNA indices for the aneuploid populations varied f rom 1.09 to 1.96, the median DNA index being 1.20. A combination of al ready established prognostic factors together with an optimally timed estimation of DNA synthesis activity s well as DNA content, i.e., ploi dy, might increase the predictive accuracy relative to response in the individual patient, as well as guiding the selection of dose and a pr operly timed chronotherapeutic schedule of drug delivery.