A MORPHOMETRIC ANALYSIS OF NUCLEOLI IN CULTURED CARCINOMA-CELLS OF THE HUMAN THYROID

Cells from 7 patients operated on for thyroid cancer were investigated . Samples of cells from the carcinoma and from the normal thyroid tiss ue were cultured with and without TSH stimulation. For light microscop y, serial sections of cells were cut and the size of nucleoli was meas ured and the number of nucleoli per cell counted. At the electron micr oscopic level the number and the volume of the fibrillar centres (FC) were estimated taking the Swiss cheese effect into account. The areal densities of FC, the fibrillar and granular component in nucleoli were determined by point counting. The results indicate that the malignant transformation has no influence on the size of the FC, but the observ ed numbers as well as the total area of FC are larger in cancer cells than in the normal thyroid epithelial cells. The nucleolar density of the fibrillar component is larger and that of the granular component i s smaller in thyroid carcinoma cells than in non-malignant thyroid epi thelial cells (p = 0.0001). Thus simple morphometry at the electron mi croscopic level might be helpful to discriminate between thyroid epith elial cells and thyroid carcinoma cells in culture.