Electron-Microscopic Examination of Human Milk Particularly from Women Having Family Record of Breast Cancer.

Abstract
10 samples of human milk collected from young, healthy, nursing women, whose sisters, mothers, or grandmothers had breast ancer, were examined with the aid of an electron microscope. Spherical particles of a smooth surface and a high density to the electron beam, varying in diameter from 20-200 m[mu], in some nstances grouped in pairs or clusters, were found in all samples; hey were particularly numerous in 5 of the 10 samples examined. These spherical particles appeared to be similar to those previously observed in mouse milk known to contain the mouse nammary carcinoma agent. 32 control human milk samples collected from young, healthy, nursing women having a family record apparently free from any malignant tumors for 2 preceding generations, were also examined. 11 of them were found to ontain spherical particles essentially similar to those described bove. Of the remaining 21 control milk samples, 17 were found to contain only occasional isolated single particles in some of the electron microscope fields, whereas the 4 other samples ppeared to be free from spherical particles, but contained come unidentified debris. No definite conclusions can be reached at this time as to the nature of the spherical particles evealed with the aid of the electron microscope in human milk.