Time-variations of pretreatment peripheral blood S + G2/M-phase size determined by flow cytometry in adult acute myeloid leukaemia

Prognostic value of S-phase cells in AML patients

Until now, reports on the cell cycle distribution of AML patients have shown highly variable results which are probably related to the technical heterogeneity of such studies. The aim of the present paper was to analyse in 204 AML patients at diagnosis the proliferative rate (assessed by the number of S-phase cells) of peripheral blood (PB) (126 cases) and bone marrow (BM) (78 cases) cells in order to explore its relationship with disease characteristics. A strong parallelism was observed regarding the relationship between the proliferative rate of the blast cells both in PB and in BM and the disease characteristics. Cases with a high proliferative rate were associated with advanced age, high WBC counts and LDH serum levels, monocytic leukaemias (assessed both by morphological and immunophenotypic criteria) and NK-associated antigens (CD56, CD16). The proliferative activity did not influence the CR rate; in contrast, cases with a high number of S-phase cells had shorter survival. In addition, multivariate analysis showed that age, the expression of CD11b, and the S-phase counts are the only three prognostic factors displaying an independent impact on survival.

Circadian rhythms and cancer chemotherapy

Experimental and clinical pertinent data regarding circadian rhythmicities are reviewed in (1) target tissues, i.e., healthy tissues (actively proliferating or not) and tumor tissues, (2) pharmacology of anticancer agents, (3) toxicity and tolerance of these agents and (4) antitumor activity of cancer chemotherapy. The basic concepts of chronotolerance and/or of chronoefficacy have brought new hopes for further amelioration in the management of cancer patients. Quite recent published Phase II and III clinical trials have demonstrated that new improvements on the therapeutic index have been achieved through ambulatory chronotherapy for various solid tumors.