G. Palestro et al., BIOLOGICAL HETEROGENEITY OF DIFFUSE MIXED SMALL AND LARGE-CELL NON-HODGKINS-LYMPHOMAS ASSESSED BY DNA FLOW-CYTOMETRY AND KI67, Leukemia & lymphoma, 19(5-6), 1995, pp. 467-472
The cell proliferative activity of the clinico-pathologically heteroge
neous non-Hodgkin's lymphomas (NHL) included in the intermediate grade
F category of the Working Formulation (WF) was investigated. S-phase
fraction with flow cytometry on cell suspensions, and Ki67 on frozen t
issue sections were performed in 42 F NHL. An avidin-biotin immunocomp
lex method was used and 1000 cells from 10 representative fields were
counted. DNA content, S-phase and Ki67 were also detected in 194 NHL c
overing the whole spectrum of the WF. DNA content anomalies were found
in 52 of 194 NHL. Their incidence, like that of S-phase fraction and
Ki67 positive cells, progressively increased from low- to high-grade.
A linear correlation was found between Ki67 and S-phase (r = .59). Usi
ng the median value of proliferating cells obtained with both procedur
es as a cut off, two very different groups of lymphomas could be disti
nguished within a series of 42 F-intermediate NHL: with low and high p
roliferative cell activity (p < .0001) that were termed F-low and F-hi
gh, respectively. A intermediate group was placed between them. It dif
fered significantly from the others if Ki67 was used but only from the
F-high group if the S-phase fraction analysis was applied. No signifi
cant differences were seen when comparing F-low with the single catego
ries of low-grade NHL and F-high with H high-grade NHL; no significant
differences were found between F-high and G, and between G and H cate
gories. The existence of distinct groups of NHL in the F category, as
defined by biological parameters assessing the cell proliferative acti
vity, indicates that this category includes biologically heterogeneous
lymphoma subtypes with different grades of aggressiveness. The result
s also indicate that the G intermediate category displays proliferatio
n indices similar to those of H high grade category.