THE BIOLOGY OF TERATOMAS
n
129 transplantable teratomas. In several instances, grafts of one tumor
subline survived for long periods as nonproliferating differentiated tissues
after having flourished for three years as a transplantable tumor.
In view of the fact that the stem cells of teratomas can give rise to
fully differentiated non-neoplastic cells, Pierce and Verney (1961) have
suggested that the development of methods that would direct the differentiation of embryonal carcinoma cells to benign forms might be a
means of controlling this type of cancer.
VII. Cell of Origin
According to Willis (1962a), the nature and origin of teratomas is
one of the most controversial subjects in embryological pathology.
One theory, proposed by Budde (1926) and supported by Needham
(1950), Nicholson (1950), and Willis (1958), states that a teratoma is
an embryonic tumor arising from foci of plastic pluripotential embryonic
tissue which have escaped from the influence of the primary organizer
during early embryonic development, this escape being in some way
related to disturbances emanating from the invaginated organizing tissues of the primitive streak. There is no direct evidence to support this
theory, and there are facts and arguments which speak against it:
(1) Teratomas are much more common in the gonads than in any other
site. (2) Gonadal teratomas are more common in males of some species,
and more common in females of other species. (3) There is a laterality
preference for testieular teratomas in man and in the mouse. If the
above theory were correct, these facts would be unexpected. (4) Gonadal
teratomas can be induced in adult fowl and mice (Bresler, 1959, 1964).
One of the arguments presented to support this theory and to speak
against the theory that teratomas originate from germ cells, is that
teratomas lack "axiation" or "organization" and that they are not
"fetiform." However, in view of the fact that normal fertilized rat,
mouse, and frog ova fail to show organization when grafted to extrauterine sites (Nicholas, 1942; Runner, 1947; Fawcett, 1950b; Jollie,
1961; Rafferty, 1961), it does not seem surprising that neoplastic germ
cells in extra-uterine sites should fail to become fetiform. We grafted
two-celled strain 129 mouse eggs into the adult testis and they developed almost all of the tissues of normal mice, but showed no organization.
These growths resembled the spontaneous testieular teratomas that occur
in these mice, in that they were composed of many adult-type tissues.
Pierce et al. (1960) and Stevens (1960) transplanted embryoid bodies
(Fig. 4) derived from a transplanted testieular teratoma of a strain 129
mouse, and in the tumors derived from these grafts found formations
remarkably similar to early mouse embryos that had undergone morphogenesis. They contained what appeared to be neural folds, amnion,
n
129 transplantable teratomas. In several instances, grafts of one tumor
subline survived for long periods as nonproliferating differentiated tissues
after having flourished for three years as a transplantable tumor.
In view of the fact that the stem cells of teratomas can give rise to
fully differentiated non-neoplastic cells, Pierce and Verney (1961) have
suggested that the development of methods that would direct the differentiation of embryonal carcinoma cells to benign forms might be a
means of controlling this type of cancer.
VII. Cell of Origin
According to Willis (1962a), the nature and origin of teratomas is
one of the most controversial subjects in embryological pathology.
One theory, proposed by Budde (1926) and supported by Needham
(1950), Nicholson (1950), and Willis (1958), states that a teratoma is
an embryonic tumor arising from foci of plastic pluripotential embryonic
tissue which have escaped from the influence of the primary organizer
during early embryonic development, this escape being in some way
related to disturbances emanating from the invaginated organizing tissues of the primitive streak. There is no direct evidence to support this
theory, and there are facts and arguments which speak against it:
(1) Teratomas are much more common in the gonads than in any other
site. (2) Gonadal teratomas are more common in males of some species,
and more common in females of other species. (3) There is a laterality
preference for testieular teratomas in man and in the mouse. If the
above theory were correct, these facts would be unexpected. (4) Gonadal
teratomas can be induced in adult fowl and mice (Bresler, 1959, 1964).
One of the arguments presented to support this theory and to speak
against the theory that teratomas originate from germ cells, is that
teratomas lack "axiation" or "organization" and that they are not
"fetiform." However, in view of the fact that normal fertilized rat,
mouse, and frog ova fail to show organization when grafted to extrauterine sites (Nicholas, 1942; Runner, 1947; Fawcett, 1950b; Jollie,
1961; Rafferty, 1961), it does not seem surprising that neoplastic germ
cells in extra-uterine sites should fail to become fetiform. We grafted
two-celled strain 129 mouse eggs into the adult testis and they developed almost all of the tissues of normal mice, but showed no organization.
These growths resembled the spontaneous testieular teratomas that occur
in these mice, in that they were composed of many adult-type tissues.
Pierce et al. (1960) and Stevens (1960) transplanted embryoid bodies
(Fig. 4) derived from a transplanted testieular teratoma of a strain 129
mouse, and in the tumors derived from these grafts found formations
remarkably similar to early mouse embryos that had undergone morphogenesis. They contained what appeared to be neural folds, amnion,