Chronobiological aspects of phosphohexoseisomerase in monitoring multiple myeloma

In the field of oncology, the most important aim to date has been the finding of new means to improve the diagnosis and treatment of neoplastic diseases. Chronobiologically we have studied the behavior of phosphohexoseisomerase (PHI) in 11 multiple myeloma patients before treatment and in another group of 11 patients undergoing polychemotherapy treatment. From all patients, under the same standard conditions, 6 venous samples were taken at 4-hour intervals starting at 08.00 h, for a day. PHI serum levels were determined spectrophotometrically. The data obtained were analyzed by 'group mean cosinor' and from this analysis a mesor reduction of more than 50% was noted in subjects after polychemotherapy (M2) correlated with the absence of a circadian rhythm. The data suggest that PHI levels can be related to the characteristics of tumor growth and we feel they can be used as a guide in monitoring multiple myeloma patients.