Table Of ContentMonographs
Series Editor: U. Veronesi
The European School of Oncology gratefully acknowledges
sponsorship for the production of this monograph received
from Biofield Corp.
Springer
Berlin
Heidelberg
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Barcelona
Budapest
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London
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Santa Clara
Singapore
Tokyo
J.
M. Dixon (Ed.)
Electropotentials
in the Clinical Assessment
of Breast Neoplasia
With 24 Figures and 22 Tables
Springer
J. Michael Dixon
Department of Surgery
The University of Edinburgh
Royal Infirmary
Lauriston Place
Edinburgh EH3 9YW, U.K.
ISBN -13: 978-3-642-79996-9 e-ISBN -13: 978-3-642-79994-5
DOl: 10.1007/978-3-642-79994-5
Die Deutsche Bibliothek - CIP-Einheitsaufnahme
Electropotentials in the clinical assessment of breast neoplasia: with 22 tables 1 J. M. Dixon (ed.). -Berlin; Heidelberg;
New York; Barcelona; Budapest; Hong Kong; London; Milan; Paris; Santa Clara; Singapore; Tokyo: Springer, 1996
(Monographs 1 European School of Oncology)
ISBN -13: 978-3-642-79996-9
NE: Dixon, J. M. [Hrsg.]
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Foreword
The European School of Oncology came into existence to respond to a need for
information, education and training in the field of the diagnosis and treatment of
cancer. There are two main reasons }Vhy such an initiative was considered necessary.
Firstly, the teaching of oncology requires a rigorously multidisciplinary approach
which is difficult for the Universities to put into practice since their system is mainly
disciplinary orientated. Secondly, the rate of technological development that
impinges on the diagnosis and treatment of cancer has been so rapid that it is not an
easy task for medical faculties to adapt their curricula flexibly.
With its residential courses for organ pathologies and the seminars on new
techniques (laser, monoclonal antibodies, imaging techniques etc.) or on the
principal therapeutic controversies (conservative or mutilating surgery, primary or
adjuvant chemotherapy, radiotherapy alone or integrated), it is the ambition of the
European School of Oncology to fill a cultural and scientific gap and, thereby, create
a bridge between the University and Industry and between these two and daily
medical practice.
One of the more recent initiatives of ESO has been the institution of permanent study
groups, also called task forces, where a limited number of leading experts are invited
to meet once a year with the aim of defining the state of the art and possibly reaching
a consensus on future developments in specific fields of oncology.
The ESO Monograph series was designed with the specific purpose of disseminating
the results of these study group meetings, and providing concise and updated
reviews of the topic discussed.
It was decided to keep the layout relatively simple, in order to restrict the costs and
make the monographs available in the shortest possible time, thus overcoming a
common problem in medical literature: that of the material being outdated even
before publication.
Umberto Veronesi
Chairman Scientific Committee
European School of Oncology
Contents
Introduction
J. M. Dixon .......................................................................................................................... 1
Underlying Mechanisms Involved in Surface Electrical Potential Measurements
for the Diagnosis of Breast Cancer:
An Electrophysiological Approach to Cancer Diagnosis
R. J. Davies .......................................................................................................................... 3
A History of Direct Current Measurement as it Relates to Tissue Proliferation
M. L. Faupel........................................................................................................................ 19
Initial Preclinical Experiments with the Electropotential Differential Diagnosis
of Mammary Cancer
D. M. Long, Jr., M. 1. Faupel, Y.-S. Hsu, J. A. Escobar, J. P. Michel, 1. F. Mittag,
R. M. Mitten, B. 1. Witt, W. C. Herrick, and R. E. Keefe. .............................................. 23
Dedicated Systems for Surface Electropotential Evaluation in the Detection
and Diagnosis of Neoplasia
M. L. Faupel and Y.-S. Hsu ............................................................................................... 37
Is There a Need for a New Detection Technique for Breast Cancer?
V. Barth and J. Herrmann ................................................................................................. 45
Breast Biophysical Examination (BBE): Potential Applications in Clinical Practice
M. Merson and B. A. Bach ................................................................................................ 51
Use of Non-Directed (Screening) Arrays in the Evaluation of Symptomatic
and Asymptomatic Breast Patients
J. P. Crowe and M. L. Faupel............................................................................................. 57
The Value of BBE in the Assessment of Breast Lesions
M. Dickhaut, I. Schreer, H. J. Frischbier, and M. Merson ............................................. 63
Multicentre Clinical Trials Evaluating the Breast Biophysical Examination
in the Assessment of Breast Disease
B. A. Bach ............................................................................................................................ 71
Introduction
...1 . Michael Dixon"
Department of Surgery, The University of Edinburgh, Royal Infirmary, Lauriston Place, Edinburgh EH3 9YW,
United Kingdom
Success in the treatment of bacterial infections followed identification of differences be
tween bacterial and human cells. Although cancer cells differ biologically from cells of
the host from which they arise, it has proved difficult to exploit these biological differ
ences to improve diagnosis and treatment of solid malignancies. It has been known for
some time that there are differences in the electrical potential of normal and malignant
cells. With advances in electrode technology and the use of microprocessors it is now
possible to record direct current over the skin surface of organs such as the breast. Early
results indicate that it is possible to differentiate between benign and malignant breast
masses and furthermore, it appears possible to identify breast abnormalities in asymp
tomatic women. This represents one of the few occasions where exploration of biologi
cally recognised differences between normal and malignant cells has resulted in the de
velopment of a technique to differentiate normal and malignant tissues in vivo. As prelim
inary reports measuring skin potentials have indicated that this technique could have
considerable clinical impact on the diagnosis and management of breast cancer, it was
felt appropriate that the background scientific information and the currently available
clinical data should be summarised and presented in the form of a European School of
Oncology Monograph. Individuals involved in the initial development and clinical testing
of this technique met in June of 1994 under the auspices of the European School of
Oncology and this book is the consequence of that meeting.
* J. Michael Dixon acknowledges the support of the Cancer Research Campaign of the United Kingdom
Underlying Mechanisms Involved in Surface Electrical Potential
Measurements for the Diagnosis of Breast Cancer: An Electrophysiological
Approach to Cancer Diagnosis
Richard J. Davies
Professor of Surgery, New Jersey Medical School (UMDNJ); Chairman of Surgery, Hackensack Medical Center,
30 Prospect Avenue, Hackensack, New Jersey 07601, U.S.A.
This chapter explores at a basic level the inter The Basis of Cell Membrane Potential
face between breast cancer diagnosis, cellular
proliferation, cancer biology, epithelial ion trans
port and electrophysiology. It is not intended Cell membranes are semi-permeable lipid-pro
for the epitheliologist who wishes to under tein bilayers that behave as leaky electrical
stand more about epithelial biology, but rather capacitors. A typical cell membrane is only 7
for the epitheliologist who wishes to know how nm thick and has ions asymmetrically distrib
his discipline may interface with other, appar uted across it. These ionic gradients are main
ently unrelated ones. tained in living cells by pumps. As ions tend to
More than 30 years ago C.P. Snow acknowl diffuse from a higher concentration to a lower
edged the existence of two cultures, science one, the concentration gradient across the
and the arts or humanities [1]. Furthermore, he membrane results in an electrical potential (Vm),
urged that in order to make progress these two which in a typical cell is about 70 mV. The elec
cultures must learn to understand each other. trical field (voltage/thickness) is therefore sub
Not only has this not happened, but the cul stantial at about 100 kV/cm. This electrical field
tures of Science and Medicine themselves influences both ionic transport and carrier-medi
have become balkanized with clinicians and ated transport involving electrically charged
basic scientists failing to communicate because ions. Any change in ionic transport and perme
of the development of jargon within disciplines, ability characteristics of the cell membrane can
a reductionist approach to science, and an ex alter the electrical field. The interrelationship of
ploding volume of knowledge. Sometimes, to ionic transport and electrical field is thus com
make progress, it is necessary to think laterally plex [2].
and to explore the interface between tradition In order to illustrate the genesis of an electrical
ally narrow and isolated disciplines. Indeed, as potential across a cell membrane, one can con
Snow stated, "The clashing points of two sub sider the distribution and contribution to the
jects, two disciplines, two cultures - of two gal electrical potential of a single permeant ion such
axies, as far as that goes - ought to produce as potassium (K+). All cell membranes are
creative chances" [1]. semipermeable, which means that they are
The Biophysical Breast Examination (BBE) is permeable to some ions but not others. K+ is
a compilation of such lateral thought and inter the predominant intracellular cation. If the cell
face science, whereby observations at an ionic membrane is semi-permeable to K+ but not to
level have been translated into a new ap CI- , then K+ will diffuse across the cell mem
proach to breast cancer diagnosis. brane down its concentration gradient, resulting
in a positive electrical potential on the outside
of the cell and a negative charge on the inside
of the cell membrane. This will continue until an
electrical potential of about 61 mV is reached
4 R.J. Davies
(the Nernst potential) at which further move Cell Membrane Depolarization
ment of potassium out of the cell (flux) is op
posed because of the inside negative electrical
charge. In contrast, in this situation sodium As may be deduced from the formulas above,
(Na+), which is the predominant extracellular loss of the cell membrane electropotential (de
cation, will tend to flow down its electrical and polarization) may occur in one of three ways
chemical gradient and enter the cell. The sodi [2]:
um-potassium ATPase pump (Na/K ATPase) • Change in the concentration of the permeant
maintains the chemical gradient by pumping ions in the cytoplasm or extracellular spaoe.
sodium out of the cell and pumping potassium • Changes in the permeability of the cell mem
in, against their respective gradients. Without brane.
these gradients, and the pumps to maintain • Changes in the transport of electrogenic
them, there would be no cell membrane electri pumps.
cal potential. There may also be a direct contri All the above changes have been observed in
bution of a number of electrogenic pumps such proliferating cells, mitogenesis and malignant
as the Na/K ATPase, Ca2+ or H+ pumps to cell transformation and the changes in relation to
membrane potential. These three pumps would proliferation and cancer are discussed below.
be expected to hyperpolarize the cell mem
brane, i.e., make the outside of the cell more
positive, because they result in a net move Cell Membrane Depolarization and
ment of cations out of the cell [2]. Proliferation
Cell membranes have different permeabilities
and the concentrations of intracellular and ex
tracellular ions differ. As such they make differ In 1971 Hulser and Frank observed that the
ent contributions to the cell membrane electrical addition of serum to quiescent fibroblasts re
potential. This may be summed up in the sulted in rapid cell membrane depolarization [4].
Goldman-Hodgkin-Katz equation: The addition of serum to cultured cells is ire
quired to stimulate cell division and growth.
= _
V RT 1( PK[K]j +PNa[Nal +Pc1[C/]oJ This observation therefore led to the notion that
F 'PK[K]o + PNa[Na]o + PC1[Cn cell membrane depolarization was an early
m
event associated with cell division. Further ob
where PK, PNa and PCI are the electrodiffusive servations in other cell lines demonstrated that
permeability coefficients, [K], [Na] and [CI] refer depolarization induced by growth factors is
to the concentration of the given ion, the sub biphasic [5]. Subsequent experiments,. how
script i and 0 refers to intracellular and extra ever, showed that epidermal growth factor
cellular, respectively, RT and F refer to the gas (EGF) stimulated cell division without depolar
constant, absolute temperature and the Fara ization [6], and other authors have reported
day constant, respectively [2]. that growing or quiescent cells in culture may
Because chloride is passively distributed and have similar cell membrane Voltages. Reuss 'et
does not contribute to the cell membrane po al. reported that cultured BSC-1 epithelial cells
tential, the GHK equation may be modified to had a cell membrane voltage of -48 mV and
include the contribution of the Na/K ATPase depolarized by 5 to 20 mV following the addi
pump as follows: tion of serum or EGF [7]. This was followed lOy
J repolarization in 5-10 minutes. Although this
= -
V RT 1 ( rPK[K]j + PNa[Na]j depolarization is temporally associated with
F 'rPK[K]o + PNa[Na]o Na+ influx, the influx persists after repolariza
m
tion occurs [8]. This suggests that although the
where r is the coupling ratio of the pump initial Na+ influx may result in depolarization,
(JNa/JK) [2]. It has been estimated that the the increase in sodium transport does not
electrogenic contribution of the pump is about cease once the cell membrane has been repo
10 mV [3], although the indirect contribution is larized, possibly due to Na/K ATPase pump
much greater because of its role in maintaining activation (Fig. 1) [9].
a concentration gradient required to produce the
membrane diffusion potential.
Underlying Mechanisms in Surface Electrical Potential Measurements for Breast Cancer Diagnosis 5
-70mV -20mV Cell Membrane Depolarization and Cancer
-+---+
Studies in the 1950s and 1960s, using con
ventional intracellular glass microelectrodes,
demonstrated that cancer cells are relatively
+
depolarized compared with non-transformed
cells [27-29]. In 1971 Cone suggested a "uni
fied theory" of mitogenic control in which sus
+
tained cell membrane depolarization resulted in
continuous cellular proliferation [30-31]. It was
Fig. 1. Electrical depolarization during cell divisi~n ?r further postulated that malignant transformation
mitosis. The -70mV normal cell membrane potential IS resulted from sustained depolarization and a
dissipated to -20mV as extracellular Na+ and intracellu
failure of the cell to repolarize after cell division
lar K+ enter and leave the cell, respectively, down their
concentration gradients. This phenomenon has been [32]. In support of this view, the temperature
observed in a number of different cell types. sensitive Moloney sarcoma virus, when used
to infect and transform kidney cells in culture,
results in cell membrane depolarization which
A number of studies have confirmed that pro
precedes other transformation-specific events
liferating cells are relatively depolarized when
[33].
compared to their non-dividing or resting coun
Other studies have also demonstrated cell
terparts [10-14]. Other studies which have ex
membrane depolarization during transformation
amined alterations in ionic fluxes, intracellular
and carcinogenesis [34-36]. More recent stud
ionic composition and transport mechanisms
ies from our own laboratory have shown that
associated with mitogenesis, have indicated
there is a progressive depolarization of the
that the cell membrane potential may depolar
colonocyte cell membrane during 1,2 dimethyl
ize during cell activation and proliferation [15-
hydrazine (DMH)-induced colon cancer induc
26].
tion in CF1 mice [37]. The VA (apical membrane
Both intracellular Ca2+ (Ca2+i) and pH (pHi)
voltage) measured with intracellul~r mi?roe~ec
are increased by mitogen activation [7,18,20-
trodes in apparently "normal" colOniC epithelium
25]. These in turn may alter the gating of vari
depolarized from -74.9 mV to -61.4 mV follow
ous ion channels in the cell membrane, which
ing 6 weeks of DMH treatment; to -34 mV by
are responsible for maintaining cell membrane
20 weeks of treatment.
voltage [7,11-19]. There is thus the potential
While epithelia normally maintain their intracellu
for interaction between other intracellular mes
lar sodium concentration within a narrow range
sengers and cell membrane potential. Nonethe
[2,9], electronmicroprobe analysis suggests
less, it does not appear that cell membrane
that cancer cells exhibit cytoplasmic sodium/
depolarization is a prerequisite for cell division
potassium ratios that are 3 to 5 times greater
even though it is a frequently associated event
than those found in their non-transformed coun
in cultured cells.
terparts [38,39]. These observations may ex
None of these studies imply that cell membrane
plain in part the electrical depolarization ob
depolarization is causally related to the ons~t served in malignant or premalignant tissues,
of proliferation, only that it is frequently assocI
which could reflect the loss of K+ or Na+ gra
ated with cell mitosis or activation. A number of
dients across the cell membrane.
investigators have failed to demonstrate mito
In addition to cell membrane depolarization and
gen-induced cell membrane depolarization [8,
altered intracellular ionic activity, studies have
25-26], although the mitogens selected may
shown that there may be a decrease in electro
have "bypassed" earlier steps in the activation
genic sodium transport and activation of non
sequence, including cell membrane depolariza
electrogenic transporters during the develop
tion. One problem with many of the above
ment of epithelial malignancies [40]. These
studies is that the majority have used cultured
changes may affect or occur as a consequence
tumour cells and therefore it may be misleading
of altered intracellular ionic composition.
to extrapolate from these cells to non-trans
formed cells undergoing proliferation.
