Studies on the Mammary Tumors of Dogs

Abstract

The object of this study was tq determine the extent to which function of the mammary gland and especially its involution are dependent on the ovaries and on the suprarenal glands.. The observations were made on dogs for several reasons, namely; spontaneous mammary tumors are frequent and the neoplasms while originally local often metastasize; normal dogs have an interesting lactational rhythm in that non-pregnant females secrete milk (pseudopregnancy) twice a year; and further both suprarenal glands can be removed surgically with prolonged survival of the animal in good health, an operation as yet impossible in man (1).In dogs secretion was frequently obtained from the mammary papillae with which tumors of the breast communicate. This fluid was studied cytologically and chemically, being compared with normal milk. The amount and duration of the secretion were studied as an index of activity of the neoplastic breast. It was necessary also to collect data on the timing and extent of lactation in normal dogs, pregnant and non-pregnant. In dogs after lactation has ceased, the mammary glands do not undergo involution immediately but we found that they remain capable of stimulation by the lactogenic hormone of the hypophysis for varying lengths of time. The functional test with prolactin was of value since it is impossible from external examination of the breast of dogs in which lactation has stopped to tell whether the breast has undergone appreciable regression or is dormant and capable of functioning. This test was applied to series of normal and cancerous dogs, both intact and following removal of ovaries and suprarenal glands.Laaalio~ in Dogs.--In the dog ovulation occurs spontaneously and is followed by corpus luteum formation and the luteal phase is prolonged (35). The secretion of milk by virgin dogs was described by Heape (2) and Loisel (3) who thereby established that the presence of the fetus or decidua is not necessary for lactation. Loisel observed a female dog for more than 2 years, and discovered that vaginal bleeding and lactation occurred in a regular sequence semiannually.

Non-randomness of the anatomical distribution of tumors

“…(Spontaneous mammary tumors refer to those not caused artificially, e.g., by introducing by a virus.) In dogs, 40–60% of mammary tumors occur in the pair of glands located most caudally, i.e., near the hind legs (Bostock, 1975 ; Cotchin, 1958 ; Fidler & Brodey, 1967 ; Cotchin, 1957 ; Huggins & Moulder, 1944 ). In cats (Cotchin, 1957 ; Hayden & Nielsen, 1971 ) and mice (Prehn et al, 1954 ; Pullinger, 1952 ), most spontaneous mammary tumors occur in the anterior mammary glands, i.e., those closest to the front legs.…”

Reviews of the progress of Dairy Science: Secretion of citrate into milk

“…With oxytocin treatment the mammary epithelium was found to become permeable to citrate (48). A similar paracellular pathway may be responsible for the decreased citrate concentration observed in milk from cows with mastitis (78) or from other diseased glands such as that produced from tumour-bearing mammary glands of dogs (34).…”

Canine Mixed Tumours

“…e. ~h~~t ;~~~ 280, showing (left) the a n e (right) the zegarated by this transformation, which started at the periphery e stain). hyaliize , view taken on the potentialities of the ceUs of (1932) Huggins and Moulder (1944); Moulton adult tissues. The preformatioinal hypothesis (1954) and Ball and Douville (1931).…”

“…A high states that the tumour arises from a rest of serum alkaline phosphatase, an enzyme which embryonic tissue. The epigenetic hypothesis promotes ossification, has been found in most regards the tumour as arising from previously dogs bearing mammary tumours (Huggins and Moulder, 1944;Innes, 1952). Emphasis is placed on this method of formation by Cotchin (1947, 1954), Mulligan (1945Mulligan ( , 1949a and Willis (1948) who consider that true cartilage and bone are formed by metaplasia of connective tissue and "pseudo-cartilage" from epithelial cells.…”