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Int. J. Cancer (Pred. Oncol.): 69, 265-267 (1996)
Q 1996 Wiley-Liss, Inc.
(
Publication of the International Union Against Cancer
Publication de I'Union InternationaleContre le Cancer
MUTAGEN SENSITIVITY AS A PREDISPOSING FACTOR IN FAMILIAL
ORAL CANCER
Ravindran ANKATHIL1,4, Narayanan V. BHATTATHIRI?,
James V. FRANC IS^, K. RATHEESAN~,
B. JYOTHISH',R. CHANDINI~,
Dinesh D. ROY', Abraham K. ELIZABETH3 and M. Krishnan NAIR?
Depts. of 'Cancer Research, ?Radiotherapy and 3Cytopathology, Regional Cancer Centre, Trivandrum, India.
Pedigree analysis of the oral cancer (OC) patients registered
at our Centre had disclosed familial aggregation of oral cancer
which hitherto has not been largely reported. There is a paucity
of information on the genetic determinism for familial oral
cancer predisposition. Therefore, we investigated constitutional chromosome abnormalities and bleomycin-induced chromosome sensitivity of 7 familial and 10 sporadic oral cancer
patients and 14 unaffected family members (first-degree relatives) to determine whether these factors could give any clues
regarding cancer-predisposingfactors. Neither the oral cancer
patients nor the unaffected family members showed any constitutional chromosomal abnormalities. However, with regard to
bleomycin sensitivity, there was significant difference between
the oral-cancer patients and unaffected relatives. The mean b/c
value was I .68 f 0.48 for familial OC patients, I. I 2 f 0.36 for
sporadic OC patients and 0.52 f 0. I 8 for the unaffected family
members (p < 0.00 I). A noteworthy observation was that one
unaffected family member also showed bleomycin hypersensitivity and expressed a mean b/c value of I .32, at the initiation of
the study. That patient later developed oral carcinoma. This
clearly demonstrates that mutagen hypersensitivity among
unaffected relatives in OC families may be related to cancer
predisposition. The mutagen sensitivity study is being continued
in a larger series of subjects, for the development of a cytogenetic marker for predictionof cancer susceptibility.
8 1996
Wiley-Liss,Inc.
Carcinoma of the human oral cavity comprises a highly
prevalent cancer in India. The majority of Indian oral cancers
have been associated with habits such as chewing and/or
smoking of tobacco and consumption of alcohol. At the
Regional Cancer Centre, Thiruvananthapuram (S. India), oral
cancer constitutes about 25% of the total 6,000 new cancer
cases registered annually (Nair, 1994). A preliminary analysis
of the pedigrees of oral cancer patients registered at our
Centre had revealed familial aggregation of oral cancer
(Ankathil et al., 1996). This shows that inherited factors are
also important in oral cancer. But the genetic determinism for
oral-cancer predisposition among the family members remains
unknown. In the absence of complete information on the genes
involved, it is of interest to search for criteria to detect
individuals at risk for inherited forms of oral cancer. One
criterion may be genomic instability. Genomic instability can
be detected at the cytogenetic level by either a high rate of
spontaneous alterations or an increased sensitivity to mutagenic or clastogenic agents (Delhanty et al., 1983; Hsu et al.,
1989; Pathak et al., 1991). This study was developed on familial
and non-familial (sporadic) oral cancer patients before treatment and unaffected first-degree relatives from oral-cancer
families. The aim was to quantify the constitutional genetic
instability of these subjects through the bleomycin-induced
chromosome sensitivity assay and to determine whether this
may give any clues to cancer predisposition in oral-cancer
families.
Pedigree analysis
All the oral-cancer patients, on their first attendance at the
Clinics of Regional Cancer Centre, Trivandrum, were interviewed via a prestructured questionnaire aimed at the oncological history of first-degree relatives, with particular attention
being paid to oral cancer. O n the basis of family history
analysis, we identified 5 site-specific oral cancer families.
Three families showed aggregation of buccal mucosal cancer, 1
family showed aggregation of carcinoma of the lip and 1
showed aggregation of carcinoma of the tongue. Detailed
pedigrees of these families were prepared. The pedigree of
one of the oral cancer families is shown in Figure 1.
MATERIAL AND METHODS
In the present study, we employed short-term microcultures
of peripheral blood lymphocytes from 10 sporadic and 7
familial oral-cancer patients and 14 unaffected first-degree
relatives of familial oral-cancer patients. Lymphocytes from
each sample were cultured under 2 different sets of conditions.
The culture medium used was RPMI 1640 (DIFCO; Detroit,
MI) supplemented with 20% FBS and 0.5 ml phytohaemagglutinin (DIFCO). In culture A, cells were incubated in culture
medium alone to study the constitutional chromosome markers and the spontaneous chromosome aberrations. In culture
B, lymphocytes were cultured in culture medium and the
mutagen bleomycin was added to induce chromosomal breakage, according to the method of Hsu et al. (1991). The total
incubation time for all these cultures was 72 hr at 37°C.
Bleomycin treatment (0.03 units/ml, Nippon Kayaku, Tokyo,
Japan) was given during the last 5 hr in culture, ensuring that
damage induced in the late S and G2-phases of the cell cycle
could be evaluated at metaphase. During the last 2 hr, the cells
were treated with colcemid (0.04 Fgiml) to accumulate mitoses before being harvested for conventional air-dried preparations. All cultures were harvested by standard cytogenetic
procedures (Moorhead et al., 1960). Chromosome preparations were stained with conventional Giemsa and banded with
trypsin-Giemsa (Seabright, 1971). From each sample, 20-30
metaphases were counted and 5-10 metaphases were karyotyped to detect constitutional chromosome abnormalities.
Karyotypes were prepared according to the International
System for Human Cytogenetic Nomenclature (ISCN, 1991).
For mutagen sensitivity, chromosome breaks were scored on
100 metaphases per sample by one of us (R.A.) who was
blinded as to the case control and exposure status of the
individual. Only frank chromatid breaks or exchanges were
recorded. Each chromatid break was recorded as one break
and each chromatid exchange was recorded as 2 breaks. The
mean number of breaks per cell (b/c), based on evaluation of
100 metaphases, was taken as a measure of mutagen sensitivity. Any individual expression > 0.8 b / c was considered sensitive to bleomycin-induced chromosome damage and any individual expression above 1.0 b/c was considered hypersensitivc
(Spitz et al., 1989).
RESULTS
Constitutional chromosome abnonnalities
G-banded karyotype analysis of the lymphocytes from 10
sporadic and 7 familial oral-cancer patients and 14 unaffected
JTo whom correspondence and reprint requests should be sent, at
the Division of Cancer Research, Regional Cancer Centre, Trivandrum, India--695 011. Fax: 91 0471 447454.
Received: December 6 , 1995 and in revised form March 28, 1996.
266
ANKATHIL E T A L .
family members did not show any constitutional chromosome
abnormalities of either numerical or structural types. All these
subjects showed the normal karyotype pattern, with 46 chromosomes.
Spontaneous and bleomycin-induced chromosomal breakage
The frequencies of spontaneous chromosomal breaks were
generally low in all the subjects, ranging from 0 to 5 breaks per
100 metaphases. However, there were great variations in
bleomycin-induced chromosome breakage frequencies among
the patients and their unaffected relatives. The most predominant type of aberration was chromatid breaks. All the 17 oral
cancer patients were hypersensitive to bleomycin and expressed between 88 and 192 breaks per 100 metaphases. The
mean b / c value was 1.68 -t 0.48 for the 7 familial oral-cancer
patients and 1.12 f 0.36 for the 10 sporadic oral-cancer
patients. All the unaffected family members (except one)
expressed a lower number of breaks with a mean b / c value of
0.52 ? 0.18. The mean b / c values of the familial oral-cancer
patients were significantly higher than the values of unaffected
close relatives ( p < 0.001), as shown in Table I. A significant
observation was made in one of the families studied (Fig. 1).
Bleomycin-induced chromosome sensitivity of one familial
oral-cancer patient (patient 4) and her 3 first-degree relatives
(numbers 12, 13 and 14) had been studied 18 months previously. In this family, the proband, a female aged 59, who did
not chew, smoke or consume alcohol, had carcinoma of the
buccal mucosa and expressed a b / c value of 1.45. One of her
daughters, aged 35 (number 13 in pedigree), who also had no
habits of chewing or smoking tobacco, showed chromosome
hypersensitivity to bleomycin with a b / c value of 1.32. This
value was as high as that observed for oral-cancer patients and
so she was regularly followed up. Subsequently, 18 months
later, she presented with symptoms of buccal rnucosal cancer,
at a younger age.
DISCUSSION
It appears that genetic instability may participate in cancer
predisposition in addition to other factors and may account for
the heterogeneity of the pathologic status for a given genetic
constitution. Available reports indicate that individuals with
certain chromosomal abnormalities are more susceptible to
the development of specific types of cancer (Cohen et al., 1979;
Johnson et al., 1982; Orkin et al., 1984; Bolger et al., 1985). In
the current study, we investigated the constitutional chromosomal abnormalities, if any, associated with lymphocytes of
familial and/or sporadic oral-cancer patients. However, our
results did not confirm the existence of a direct relationship
between a given acquired chromosome alteration and a disease
state.
Hsu et al. (1989) developed the mutagen-sensitivity assay as
an indirect indicator of DNA repair competence and cancer
predisposition. It has been suggested that cancer-prone individuals have a deficiency in some step of D N A repair, which
TABLE I - BLEOMYCIN-INDUCED CHROMOSOMAL BREAKSICELL
VALUES OF THE 3 DIFFERENT SUBJECT GROUPS
$$ f~~~~
h i c range
Mean blc
Subjects
Number
Unaffected
relatives
Sporadic oral
cancer
Familial oral
cancer
14
717 30-55
0.27-0.7
10
416
53-72
0.88-1.44 1.12
7
3/4
48-59
1.21-1.92 1.68 f 0.48*
0.52
2
?
SD
0.18
* 0.36
*p < 0,001 significantly different (Student’s t-test) from unaffected relatives.
32 30 28 26
37 3 5 3 3
28 26
33 31 28
31 28 25
0
FIGURE
1 - Pegidree of an oral cancer family. Squares, males;
circles, females; numbers above symbols, identifying numbers of
family members; numbers below symbols, age at tumour diagnosis
or at last observation; U, age unknown; symbols with a diagonal,
deceased; open symbols, no neoplasm detected; solid symbols,oral
cancer.
may represent a type of genetic predisposition to cancer (Hsu
et al., 1991). In order to determine whether mutagen sensitivity
o r resistance correlates with cancer predisposition in the
oral-cancer families described here, the ability of relatives’
cells to repair chromosomal breakage induced by the mutagen
bleomycin was assayed. All the 7 familial oral-cancer patients
expressed high mutagen sensitivity with a mean b / c value of
1.68, which was significantly higher than the values of unaffected family members ( p < 0.001). All the 10 sporadic
oral-cancer patients also showed mutagen sensitivity, with a
mean b / c value of 1.12. The observation that these high
frequencies of breakage were of the chromatid type indicates
that the breakages are the result of the patients’ hypersensitivity to the mutagen bleomycin. Our study subjects included
smokers and non-smokers. But tobacco chewing and smoking,
age, gender and stage of disease did not have any impact on the
bleomycin-sensitivity profile of our study subjects. Liang et al.
(1989) reported that the levels of bleomycin-induced breaks
are generally unchanged before, during and after chemotherapy, thereby indicating that therapy has no effect on the
mutagen sensitivity of cancer patients. Even though a few
reports are available regarding increased bleomycin sensitivity
of head-and-neck cancer patients (Spitz et al., 1989; Schantz et
al., 1990; Cloos et al., 1994) no previous reports exist on the
bleomycin sensitivity of familial oral-cancer patients.
Mutagen-induced chromosome sensitivity is considered as a
constitutional factor which may be used to identify persons
with a genetic predisposition to cancer (Hsu, 1987; Cloos et al.,
1994). This has been clearly demonstrated in the oral-cancer
family shown in Figure 1. In this family, a woman aged 35, who
had no habit of chewing or smoking tobacco, showed chromosome hypersensitivity to bleomycin. She expressed a b / c value
of 1.32 which was as high as that of oral-cancer patients. Her
mother and maternal grandfather had carcinoma of the buccal
mucosa. O n follow-up, this woman later developed buccal
mucosal cancer. This was a noteworthy observation which
indicates that an elevated bleomycin clastogenicity score may
identify individuals who have a constitutional hypersensitivity
towards certain genotoxicants and may show an increased
cancer susceptibility. All other unaffected first-degree relatives
in other oral-cancer families studied were hyposensitive to
bleomycin, indicating genetic stability and/or efficient D N A
repair capabilities. Bondy et al. (1993) evaluated the selfreported cancer histories of 669 first-degree relatives of 108
patients with cancers of the upper aerodigestive tract and
MUTAGEN SENSITIVITY IN FAMILIAL ORAL CANCER
observed familial aggregation of cancer in mutagen-sensitive
patients. There are reports stating that cells of patients with
chromosome breakage syndromes such as Ataxia telangiectasia or Fanconi’s anemia are sensitive t o ionizing radiation and
a variety of alkylating agents, and these patients are more
prone to develop malignancies (Heddle et al., 1978; Paterson
and Smith. 1979; Harnden, 1985). All these observations
reiterate that genetic susceptibility t o malignancies may manifest itself a s chromosomal instability. It may be because of the
genetic instability that somatic-cell chromosomes are liable t o
spontaneous or induced breaks.
Through the bleomycin-sensitivity study, the ability of a n
individual’s cells to repair bleomycin-induced chromosome
breakage can b e assayed. T h e mutagen hypersensitivity of the
7 patients in these 5 oral-cancer families suggests a common
genetic determinant that may b e an important predisposing
factor for cancer development. It is likely that the affected
267
individuals have deficiencies in their general cancer-protective
mechanisms such as those of DNA repair and recombination
which are essential for maintaining the integrity of their DNA.
Bleomycin-hypersensitive individuals may be deficient in the
repair genes that affect the efficiency of repair of the DNA
lesions induced by bleomycin. Hence it is reasonable to assume
that, in oral-cancer families, unaffected members who are
bleomycin-hypersensitive may be at an increased risk of cancer
susceptibility. We are continuing serial studies of mutagen
sensitivity in oral-cancer families with the aim of developing a
cytogenetic marker for prediction of cancer susceptibility.
ACKNOWLEDGEMENT
The authors thank Ms. P.T. Latha and Ms. Anitha Nayar,
social investigators of our centre for their support and Ms. L.
Remadevi, for secretarial assistance.
REFERENCES
ANKATHIL,
R., MATHEW,A., JOSEPH,F. and KRISHNAN
NAIR,M., Is
oral cancer susceptibility inherited? Report of 5 oral cancer families.
Oral Oncol., 32B, 63-67 (1996).
BOLGER,G.B., STAMBERG,
J., KIRSCH,I.R., HOLLIS,G.F. and
SCHWARTZ-THOMAS,
G.H., Chromosome translocation t(14;22) and
oncogene variant in a pedigree with familial meningioma. New Engl. J.
Med., 312,564-567 (1985).
BONDY,M.L., SPITZ.M.R., HALABI,
S., FUEGER,J.J., SCHANTZ,
S.P.,
SAMPLE,D. and Hus, T.C., Association between family history of
cancer and mutagen sensitivity in upper aerodigestive tract cancer
patients. Cancer Epidemiol. Biomarkers Prev., 2,103-106 (1993).
CLOOS,J., BRAAKHUIS,
B.J., STEEN,I., COPPER,M.P., DE VRIES,N.,
NAUTA,J.J. and SNOW,G.B., Increased mutagen sensitivity in head
and neck squamous cell carcinoma patients, particularly those with
multiple primary tumours. Int. J. Cancer, 56,816-819 (1994).
COHEN,A.J., LI, F.P., BERG,S., MARCHETTO,
D.J., TSAI,S., JACOBS,
S.C. and BROWN,
R.S., Hereditary renal cell carcinoma associated with
a chromosomal translocation. New Engl. J. Med., 301,592-595 (1979).
DELHANTY,
J.D.A., DAVIS,M.B. and WOOD,J., Chromosome instability in lymphocytes, fibroblasts and colon epithelial-like cells from
patients with familial polyposis coli. Cancer Genet. Cyfogenet.,8,27-50
(1983).
HARNDEN,
D.G., Inherited factors in leukaemia and lymphoma. Leuk.
Rex, 9,705-707 (1985).
HEDDLE,
J.A., LUE,C.B., SAUNDERS,
E.F. and BENZ,R.D., Sensitivity
to five mutagens in Fanconi’s anemia as measured by the micronucleus
method. Cancer Res., 38,2983-2988 (1978).
Hsu, T.C., Genetic predisposition to cancer with special reference to
mutagen sensitivity.In vitro Cell Devel. Biol., 23,591-603 (1987).
Hsu, T.C., JOHNSTON,
D.A., CHERRY,
L.M., RAMKISSOON,
D., SCHANTZ,
S.P., JESSUP,J.M., WINN,R.J., SHIRLEY,
L. and FURLONG,
C., Sensitivity to genotoxic effects of bleomycin in humans. Possible relationship
to environmental carcinogenesis. Int. J. Cancer, 43,403409 (1989).
Hsu, T.C., SPITZ,M.R. and SCHANTZ,S.P., Mutagen sensitivity-a
biological marker for cancer susceptibility. Cancer Epidemiol. Biomark.
Prev., 1 , 8 3 4 9 (1991).
ISCN, Guidelines for cancer cytogenetics: Supplement to An International System for Human Cytogenetic Nomenclature. F. Mitelman
(ed.), S. Karger, Basel (1991).
JOHNSON,
M.P., RAMSAY,
N.. CERVANKA,
J. and WANG,N., Retinoblastoma and its association with a deletion in chromosome 13. A survey
using high-resolution chromosome techniques. Cancer Genet. cy60genet., 6,29-37 (1982).
LIANG,J.C., PINKEL,
D.P., BAILEY,N.M. and TRUJILLO,
J.M., Mutagen
sensitivity and cancer susceptibility. Report of a cancer prone family.
Cancer, 64,1474-1479 (1989).
MOORHEAD,
P.S., NOWELL,P.C., MELLMANN,
W.J., BATTIPPS,D.W.
and HUNGERFORD,
D.A., Chromosome preparations of leukocytes
cultured from human peripheral blood. Exp. Cell Res., 20, 613-616
(1960).
NAIR,M.K., Regional Cancer Centre-Trivandrum, India. Annual
Report (1994).
ORKIN,S.H., GOLDMAN,
D.S. and SALLAN,S.E., Development of
homozygosity for chromosome tip markers in Wilms’ tumour. Nature
(Lottd.), 309,172-174 (1984).
PATERSON,
M.C. and SMITH,P.J., Ataxia telangiectasia-an inherited
human disorder involving hypersensitivity in ionizing radiation and
related DNA-damaging chemicals. Ann. Rev. Genet., 13, 291-318
(1979).
PATHAK,S., HOPWOOD,V.L., HUGHES.J.I. and JACKSON,G.L.,
Identification of colon cancer-predisposed individuals. A cytogenetic
analysis.Amer. J. Gastroenterol., 86, 676-684 (1991).
SCHANTZ,
S.P., SPITZ,M.R. and HSU,T.C., Mutagen sensitivity in head
and neck cancer patients: a biologic marker for risk of multiple
primary malignancies. J. naf. Cancer Znst., 82, 1773-1775 (1990).
SEABRIGHT,
M., A rapid banding technique for human chromosomes.
Lancet., ii, 971-972 (1971).
SPITZ,M.R., FUEGER,
J.J., BEDDINGFIELD,
N.A., ANNEGERS,
J.F., Hsu,
T.C. and NEWALL,G.R., Chromosome sensitivity to bleomycininduced mutagenesis-an independent risk factor for upper aerodigestive tract cancers. Cancer Res., 4 9 , 4 6 2 H 6 2 8 (1989).
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