1062-3604/04/3502- © 2004
Russian Journal of Developmental Biology, Vol. 35, No. 2, 2004, pp. 57–61. Translated from Ontogenez, Vol. 35, No. 2, 2004, pp. 85–90.
Original Russian Text Copyright © 2004 by R. Stoika, Panchuk, B. Stoika.
There are similar features between embryogenesis
(development of the embryo from a fertilized egg) and
carcinogenesis (development of the tumor from a
malignant somatic cell), which are expressed at the
cytomorphological, biochemical, and regulatory levels.
Since embryogenesis is a normal physiological process
and carcinogenesis is a pathological process, it is nec-
essary to understand on which mechanisms an excep-
tional malignant transformation in normal development
is based. It is also necessary to establish which mecha-
nisms prevent malignization of embryonic cells, which
are in many features similar to malignant cells.
In this review we concentrated our attention on sim-
ilarities of some regulatory mechanisms acting in both
embryonic and tumor cells, speciﬁcally those depend-
ing on polypeptide growth factors. These latter are hor-
mone-like substances, which, unlike the “classical”
hormones, mostly use the paracrine or autocrine mech-
anisms of regulation of proliferation, differentiation,
and apoptosis. In order to better understand the role of
polypeptide growth factors in embryogenesis and car-
cinogenesis, it is more advisable to establish ﬁrst the
similarities between these processes.
PARALLELISMS OF EMBRYOGENESIS
Autonomous proliferative potential.
typic feature is, in all likelihood, due to the functioning
of several regulatory mechanisms, such as (1) expres-
sion of oncogenes whose products are involved in trig-
gering cell cycle, (2) production of growth stimuli with
autocrine mechanism of action, and (3) provision of
cell proliferation due to a better vascularization of the
corresponding tissues (Lodish
, 2000). The func-
tioning of these mechanisms in embryonic and tumor
cells is characterized in detail below.
Low level of differentiation.
It is well known that
embryonic cells are low specialized and preserve a high
differentiation potential. At the same time, tumor cells,
despite a certain specialization, are characterized by a
low differentiation potential. In addition, tumor cells
often lack some tissue speciﬁc antigens and, at the same
time, express embryo speciﬁc antigens (see below).
Relative resistance against apoptosis.
massive cell death takes place in some parts of the
embryo during morphogenesis, as well as in the central
part of solid tumor, the embryonic and tumor cells are
characterized, as a whole, by a high antiapoptotic
potential (Fil’chenkov and Stoika, 1999). This is
enhanced, above all, by the activities of regulatory
mechanisms preventing apoptosis, such as expression
of the telomerase gene in embryonic stem cells and
cells of many tumors. It is known that telomerase
enhances the restoration of the normal length of chro-
mosome telomere regions shorted during DNA replica-
tion. The cells of normal tissues that lost contacts with
the neighboring cells rapidly perish by way of apopto-
sis and this phenomenon was called anoicosis
(Fil’chenkov and Stoika, 1999). At the same time,
tumor cells can survive anoicosis, which ensures their
potential for metastatic spreading.
Autocrine regulation mediated by polypeptide
As a matter of fact, the cells producing
certain bioregulators are themselves targets of their
action, since they have speciﬁc receptors. This type of
regulation is convenient for both the embryo, whose
developmental rate little depends, in a certain sense,
from the mother and from the tumor, which escapes the
regular control of the tumor bearing organism.
Parallels and Antagonisms of Embryogenesis and Carcinogenesis
R. S. Stoika*
**, R. R. Panchuk*
**, and B. R. Stoika***
* Institute of Cell Biology, National Academy of Sciences of Ukraine, ul. Dragomanova 14/16, Lviv, 79005 Ukraine
** Ivan Franko Lviv National University, Grushevskogo ul. 4, Lviv, 79005 Ukraine
*** Danylo Halytsky Lviv State Medical University, Pekarskaya ul. 52, Lviv, 79010 Ukraine
Received March 10, 2003; in ﬁnal form, August 8, 2003
—The main similarities of embryonic and tumor cells, as well as the mechanisms preventing the
malignant transformation of embryonic cells, are presented in this review. Special attention is paid to the role
of speciﬁc polypeptide growth factors in reciprocally excluding processes: embryogenesis and carcinogenesis.
Based on the presented analysis, new potential targets for antitumor drugs are considered.
: embryogenesis, carcinogenesis, polypeptide growth factors.