Nuclear-Nucleolar Volume Ratio in Cancer

Abstract

In the study of tumor cytology, attention has been drawn in recent years to the importance of the size of the nucleolus. The diagnostic significance of nucleolar size in relation to the nucleus of cancer has been championed for several years by W. C. MacCarty, who with Haumeder in 1934 published a statistical study on the size of the nucleolus in malignant growths and normal tissues. He concluded that a great difference exists between the size of the nucleoli of cancer cells and of regenerative forms, such as fibroblasts, endothelioblasts, and other immature cells. The present study was begun in the early part of 1933, before the appearance of MacCarty9s statistics, in an attempt to determine by means of direct measurement whether or not a significant difference exists between the N/n 1 ratio of malignant tissues and that of non-malignant cells. Little is known of the physiological activity of the nucleolus. From a study of the lower animals it appears probable that the nucleoli are concerned in cell metabolism. Beams and Wu (1929) and Wu (1930) in a study of the spinning glands of certain insects found that the nucleolus plays an important role in secretion. Gardiner (1927) concluded from a study of the cells of the crab that the nucleoli have an important function in yolk formation and also that they are probably concerned with phosphorus metabolism. Benoit (1921) studied the epididymis of the higher mammals, and Ludford (1925), who investigated the same organ in the mouse, concluded that the nucleoli played an important role in secretion of the cell. Increase in the size of nucleoli was seen by Sayles during regeneration of the hypoderm of Lumbriculus. Ludford (1922), on the basis of a large series of experiments, was inclined to regard the size of nucleoli as an indication of the degree of metabolism existing in the cell; the greater the metabolic activity the larger the total volume of nucleolar material present in the nucleus.