COMMENTARY - THE MAMMARY FAT PAD

The mammary fat pad is essential for development of the mammary epithe lium, providing signals that mediate ductal morphogenesis and, probabl y, alveolar differentiation. The ''cleared'' fat pad is often used as a transplantation site. Considering the crucial role of the fat pad, i ts properties have received relatively little attention from researche rs in the field. Some of the questions whose investigation is pertinen t to understanding both normal mammary development and carcinogenesis are outlined in this commentary in the spirit of stimulating enquiry i nto this important subject. It is clear from a brief perusal of the av ailable literature that until studies are specifically designed to cle arly differentiate between functional effects of the fibrous and the a dipose stroma, more substantive information about their differential e ffects on mammary development and tumorigenesis will not be forthcomin g.