Enhanced expression of hedgehog signaling molecules in squamous cell carcinoma of uterine cervix and its precursor lesions
Enhanced expression of hedgehog signaling molecules in squamous cell carcinoma of uterine cervix and its precursor lesions
Yan Hua Xuan 0 7
Hun Soon Jung 1
Yoon-La Choi 2
Young Kee Shin 1
Hee Jin Kim 3
Kyung Hee Kim 4
Wun Jae Kim 5
You Jeong Lee 6
Seok-Hyung Kim 0
0 Department of Pathology, Chungbuk National University College of Medicine , Cheongju, Chungbuk , Korea
1 Department of Pharmacy, Research Institute of Pharmaceutical Science, College of Pharmacy, Seoul National University , Seoul , Korea
2 Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul , Korea
3 Department of Diagnostic Labortory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul , Korea
4 Department of Pathology and Molecular Medicine, Eulji University School of Medicine , Daejeon , Korea
5 Department of Urology, Chungbuk National University College of Medicine , Cheongju, Chungbuk , Korea
6 Department of Pathology, Seoul National University, College of Medicine , Seoul , Korea
7 Department of Pathology, Yanbian University College of medicine , Yanji , China
The hedgehog (Hh)-signaling pathway plays an essential role in normal development. Deregulation of this pathway is responsible for several types of cancers. The aim of this study was to determine the expression pattern and the extent of Hh-signaling molecules in squamous cell carcinoma of uterine cervix and its precursor lesions. A total of 106 uterine cervical cancers and related lesions (37 squamous cell carcinomas, 23 cervical intraepithelial neoplasia (CIN) III, 10 CIN II, four CIN I, 32 normal cervical epithelia) were immunohistochemically analyzed with anti-Shh, Indian Hh (Ihh), Patched (PTCH), Smoothened (Smo), Gli-1, Gli-2, Gli-3 antibodies on paraffin blocks. The results showed that the expression of all the Hh-signaling molecules was greatly enhanced in uterine cervical tumors, including carcinoma and its precursor lesions. The staining pattern was mainly cytoplasmic except for Gli-1/2, whose expression was observed in both cytoplasm and nucleus. In case of Ihh, PTCH, Smo and Gli-1, their expression in normal epithelium was completely absent or rare. The expression of all the seven Hh-signaling molecules mentioned above was significantly increased in CIN II/III and carcinoma, compared with that in normal epithelium (Po0.05). The expression of Shh was increased by double; the first increase occurred in normal epithelium-CIN transition, and the second, during the progression of CIN to carcinoma. These results strongly suggest that the Hh-signaling pathways were extensively activated in carcinoma and CIN of uterine cervix. In conclusion, the Hh-signaling pathways may be involved in carcinogenesis of squamous cell carcinoma of uterine cervix and can be considered as a potential therapeutic target. Modern Pathology (2006) 19, 1139-1147. doi:10.1038/modpathol.3800600; published online 16 June 2006
sonic hedgehog; patched; smoothened; Gli; squamous cell carcinoma; uterine cervix
Hedgehog (Hh) is a family of secreted proteins and
the Hh-signaling pathway has been known to play
central roles in directing the embryonic pattern
formation during development and to be involved in
the regulation of stem cell renewal in adult tissue.1
In human development, the Hh-signaling pathway is
crucial for the decision making of left-right
asymmetry and patterning of various organs including the
brain, spinal cord, craniofacial structures, lung,
teeth, eye, and hair. However, during the
postembryonic period, the Hh-signaling pathway has
been known to be involved in the regulation of
adult tissue stem cells during the regeneration of
adult tissue after damage.1,2?4
In mammals, three hedgehog (Hh) homologues
have been identified: Sonic (Shh), Indian, and
Desert. The Hh proteins activate a membrane?
receptor complex and this, in turn, by means of
cytoplasmic signal transduction, activates Gli
zincfinger transcription factors. The receptor complex is
formed by Patched (PTCH) and Smoothened (Smo),
where PTCH normally inhibits Smo. When Hh binds
to PTCH, this repression of Smo by PTCH is
released, allowing Smo to activate the Gli protein.5
The Gli proteins are large and multifunctional
transcription factors, and there are three Gli proteins
that behave differently with partially redundant
functions; Gli1 and Gli2 can mediate Hh signals
and have been implicated in tumorigenesis. Gli-1 is
known to function primarily as an oncogene if
tumors arise due to overexpression. On the other
hand, Gli-2 and Gli-3 function as oncogenes or
tumor suppressors, depending on the type of
mutation and cellular context.6
The deregulation of Hh-signaling pathway has
been implicated in several types of cancers.2?4 The
mutational activation of the Hh-signaling pathway,
whether sporadic or in Gorlin?s syndrome, is
associated with tumorigenesis in a small subset of
these tissues, predominantly skin, the cerebellum,
and skeletal muscle.7,8 Furthermore, extensive
activation of the Shh-signaling pathways has
been reported in cancers of other organs, such as
small cell lung cancer,9,10 carcinomas of esophagus,
stomach, pancreas, biliary tract, and prostate,1 and
Approximately 10 370 new cases of cervical
cancers and 3710 deaths were anticipated in the
United States in 2005.12 Cervical cancer is also an
important health problem in adult women in
developing countries, where it is the most or second
most common cancer among women.13 Cervical
cancer claims the lives of 231 000 women annually
worldwide.13 Even a conservative estimate of the
global prevalence suggests that there are 1.4 million
cases of clinically recognized cervical cancer each
year. It is also estimated that 3?7 million women
worldwide may have high-grade dysplasia.13
Although the importance of the Hh signaling in
tumor development is recognized in various organs,
there has been no study regarding the expression of
Hh-signaling molecules in uterine cervical tumors.
In this study, we conducted a comprehensive
analysis of the expression of Hh-signaling molecules
at the protein level via immunohistochemistry in
uterine cervical cancer and its precancerous lesions.
The results demonstrated that the increased and
persistent expression of Hh-signaling molecules
may be implicated in carcinogenesis of uterine
Materials and methods
Patients, Tissue Samples, and Reagents
We investigated 106 cases of uterine cervical
carcinomas and their related lesions, obtained from
the surgical pathology files at the Department of
Pathology, Chungbuk National University Hospital.
The criteria for inclusion were the histopathologic
diagnosis of uterine cervical lesions and the
availability of paraffin-embedded tissue specimens. The
selected cases consisted of 37 cases of squamous cell
carcinoma, 23 cases of CIN III, 10 cases of CIN II,
four cases of CIN I, and 32 cases of normal cervical
epithelium. This study was approved by the
institutional review board of Chungbuk National
The pathologic slides were reviewed to analyze
pathologic parameters, including tumor size, depth
of invasion, and the presence of nodal metastasis.
The 37 squamous cell carcinomas (age range ? 22?
69 years; average age ? 46 years) encompassed 29
early cases (pTNM stage I ? 27, pTNM stage II ? 2)
and eight advanced cases (pTNM stage III ? 8). The
TNM staging was assessed according to the staging
system established by the American Joint Committee
on Cancer (AJCC).14
Tissue microarray slides were employed for the
purpose of effective detection. For preparation of
these slides, we punched tissue columns (3.0 mm in
diameter) from the original blocks and inserted them
into new paraffin blocks (each containing 30 holes
to accept the tissue columns). Consequently, serially
sectioned slides were prepared. Each tissue
microarray slide (1 3 in) could hold 30 specimens,
allowing us to analyze 30 specimens simultaneously
with a minimum variation during the staining
process. Each specimen was round in shape and
3.0 mm in diameter, thereby providing a sufficient
amount of tissue for histopathologic analysis.
All archival materials were routinely fixed in 10%
neutral-buffered formalin and embedded in paraffin.
Sections (4 mm) were prepared on silane-coated
slides (Sigma, St Louis, MO, USA). The
immunostaining kits were purchased from DAKO Inc.
The Immunohistochemical Staining Procedure
The tissue sections in the microslides were
deparaffinized with xylene, hydrated in serial dilutions of
alcohol, and immersed in 3% H2O2 to quench
endogenous peroxidase activity. The sections were
then microwaved in 40 mM Borate buffer (pH 8.2)
supplemented with 1 mM EDTA and 1 mM NaCl for
20 min for antigen retrieval.15,16 Tris-EDTA buffer
(Tris 40 mM, EDTA 1 mM, pH 10.0) was also used as
a retrieval buffer. The tissues were then incubated
with several primary antibodies (anti-Shh, anti-Ihh,
anti-PTCH, anti-Smo, anti-Gli1, anti-Gli2, and
antiGli3). The dilution ratio and optimal retrieval buffer
of each antibody are shown in Table 1. Primary
antibody incubation was carried out for 60 min,
followed by three successive rinsings with a
washing buffer. Further incubation was performed with
dextran polymer conjugated with peroxidase and
goat anti-rabbit Ab (DAKO, Envision plus) for
an additional 20 min at room temperature. After
rinsing, the slides were washed and the chromogen
was developed for 5 min with liquid 3,
30-diaminobenzidine (DiNonA, Seoul, South Korea). The slides
were counterstained with Meyer?s hematoxylin,
dehydrated, and mounted with Canada balsam for
examination. We used distilled water with 0.1%
tween 20 as a rinsing solution.17
1, Gli-2, Gli-3) in squamous cell carcinoma and its
precursor lesions of uterine cervix via
immunohistochemistry. First, the average intensity was
analyzed (the mean of IS from immunostaining).
Then the Shh expression in terms of the rate of
high expression was analyzed.
Evaluation of Results of Immunohistochemical
We used the Sinicrope et al?s
18 scoring method
) to evaluate both the intensity of
immunohistochemical staining and the proportion of the
stained epithelial cells. The staining intensity was
subclassified as follows: 1, weak; 2, moderate; or
3, strong. The positive cells were quantified as a
percentage of the total number of epithelial cells and
the proportions were assigned to one of five
categories: 0, o5%; 1, 5?25%; 2, 26?50%; 3, 51?
75%; and 4, 475%. The percentage of positivity of
the tumor cells and the staining intensity were then
multiplied in order to generate the
immunoreactivity score (IS) for each of the tumor specimens.
Cytosolic and nuclear stainings were independently
analyzed. Each lesion was separately examined and
scored by two pathologists (XYH and SHK). Cases
with discrepant scores were discussed to obtain a
Statistical analyses were conducted using Fisher?s
exact tests, Pearson?s w2 tests, ANOVA, Mann?
Whitney tests, Kruskal?Wallis test, Tukey?s HSD,
and Duncan?s test (as a post hoc test). P-values
o0.05 were regarded to be statistically significant.
All statistical analyses were performed using the
SPSS software (SPSS Inc., Chicago, IL, USA).
The Expression Pattern of Hh-Signaling Molecules in
Squamous Cell Carcinoma of Uterine Cervix and Its
We analyzed the expression pattern of Hh-signaling
molecules (ie Shh, Indian Hh (Ihh), PTCH, Smo,
In case of Shh, the expression was observed in the
cytoplasm of both glandular component and
squamous epithelium of normal uterine cervical
epithelium; however, the level was low (IS: 1.571.1). In
squamous epithelium of the cervix, Shh was mainly
expressed in basally located cells (Figures 1 and 2).
However, its expression level was significantly
increased in cervical intraepithelial neoplasia (CIN
I, IS: 3.571.9; CIN II, IS: 3.471.2; CIN III, IS:
3.871.5) compared with in normal epithelium (IS:
1.571.1) (Po0.005) (Figures 1 and 3, Table 2). The
level of Shh expression was also increased
significantly in squamous cell carcinoma (IS: 5.771.5)
compared with in CINs with a statistical
significance (Po0.001) (Figures 1 and 3, Table 2). We
also analyzed the Shh expression in terms of the
rate of high expression, which was defined by
IS higher than 3 (Table 3). In normal epithelium
Shh high expression was rare (3/32, 9%). The rate
was significantly increased in CIN (CIN I: 2/4,
50%. CIN II: 6/10, 60%. CIN III: 15/22, 68%) and
even higher in carcinomas (35/37, 95%) (Po0.001)
The Ihh expression was very rare and almost
completely absent in normal uterine cervical
epithelium. However, aberrant expression of Ihh was
frequently observed in CIN II, CIN III and squamous
cell carcinoma (Figures 1 and 3). The level of Ihh
expression was significantly increased in CIN II (IS:
2.071.5), CIN III (IS: 2.771.5) and carcinoma (IS:
2.972.4), compared with in normal epithelium
(IS: 0.170.4) (Po0.001) (Table 2). The rate of high
expression (IS43) was zero in normal epithelium
(0/25) and was significantly increased in CIN III
(6/22, 27%) and carcinoma (13/37, 35%) (Po0.05)
Modern Pathology (2006) 19, 1139 ?1147
In normal epithelium PTCH was expressed in 5 of
25 cases (20%) (Figure 1). The average staining
intensity (IS) increased significantly in CIN II (IS:
2.071.5), CIN III (IS: 2.771.5), and carcinoma
(IS: 2.972.4), compared with normal epithelium
(IS: 0.170.4) (Po0.001) (Table 2). The rate of high
expression (IS43) was low in normal epithelium (0/
25, 0%) and CIN II (1/9, 11%), but substantially and
significantly increased in CIN III (11/22, 50%) and
carcinoma (22/37, 60%) with a statistical
significance (Po0.001) (Table 3).
Smo expression was also rare and was found in only
two out of 27 cases (Figure 1). The average intensity
was extremely low in normal epithelium (IS:
0.170.3) and was significantly increased in
neoplastic lesions including CIN I/II/III (IS: 2.771.5/
2.672.1/2.171.7, respectively), and carcinoma (IS:
3.272.4) (Po0.001) (Figures 1 and 3, Table 2). The
rate of high expression (IS43) was also zero in
normal epithelium (0/27, 0%), but was increased
significantly in tumorous lesions such as CIN I (1/3,
33%)/CIN II (4/9, 44%)/CIN III (5/21, 24%) and
carcinoma (18/37, 49%) (Po0.001) (Table 3).
In contrast to the other Shh-signaling molecules
whose expressions were observed mainly in
cytoIS, immunostaining score; CIN, cervical intraepithelial neoplasm; NL, normal epithelium.
Shh: NL vs CIN I/II/III and carcinoma: Po0.025, CIN I/II/III vs carcinoma: Po0.05.
PTCH: NL vs CIN II/III and carcinoma: Po0.005, CIN II vs carcinoma: Po0.005.
Smo: NL vs CIN I/II/III and carcinoma: Po0.001, Ihh: NL vs CIN II/III and carcinoma: Po0.005.
Gli1(C): NL vs CIN II/III and carcinoma: Po0.001, CIN I vs CIN III and carcinoma: Po0.025.
Gli1(N): NL vs CIN II/III and carcinoma: Po0.01.
Gli2(C): NL vs CIN II/III and carcinoma: Po0.01, Gli2(N): NL vs CIN I/II/III and carcinoma: Po0.05.
Gli3(C): NL vs CIN II/III and carcinoma: Po0.001, CIN I/II vs carcinoma: Po0.05.
Carcinoma 37 35/37 (95%) 13/37 (35%) 22/37 (60%) 18/37 (49%) 8/36 (22%) 2/36 (6%) 4/38 (11%) 26/38 (68%) 30/36 (83%)
CIN III 23 15/22 (68%) 6/22 (27%) 11/22 (50%) 5/21 (24%) 7/23 (30%) 3/23 (13%) 2/22 (9%) 16/22 (73%) 18/22 (82%)
CIN II 10 6/10 (60%) 1/7 (14%) 1/9 (11%) 4/9 (44%) 0/8 (0%) 2/8 (25%) 1/8 (13%) 5/8 (63%) 5/8 (63%)
CIN I 4 2/4 (50%) 0/3 (0%) 1/3 (33%) 1/3 (33%) 0/3 (0%) 0/3 (0%) 0/4 (0%) 1/4 (25%) 1/3 (33%)
Normal 32 3/32 (9%) 0/25 (0%) 0/25 (0%) 0/27 (0%) 0/29 (0%) 0/29 (0%) 0/29 (0%) 3/29 (10%) 0/25 (0%)
P-value o0.001 o0.05 o0.001 o0.001 o0.025 0.102 0.471 o0.001 o0.001
CIN, cervical intraepithelial neoplasm. NL, normal epithelium.
Shh: NL vs CIN I/II/III and carcinoma: Po0.05, CIN I/II/III vs carcinoma: Po0.01.
PTCH: NL vs CIN I/III and carcinoma: Po0.01, CIN II vs CIN III and carcinoma: Po0.05.
Smo: NL vs CIN I/II/III and carcinoma: Po0.01, Ihh:NL vs CIN III and carcinoma: Po0.01.
Gli1(C): NL vs CIN III and carcinoma: Po0.01.
Gli2(N): NL vs CIN II/III and carcinoma: Po0.01.
Gli3(C): NL vs CIN I/II/III and carcinoma: Po0.01, CIN I vs carcinoma: Po0.05.
plasm, Gli-1/2 molecules were expressed in both
cytoplasm and nucleus. The cytoplasmic expression
of Gli-1 was completely absent in normal
epithelium, but aberrant expression of the protein was
frequently observed in CIN II/III and carcinoma
(Figure 1). The average intensity of cytoplasmic
Gli1 expression significantly increased in CIN II (IS:
1.671.3)/CIN III (IS: 2.671.6) and carcinoma (IS:
1.971.7), compared with in normal cervical
epithelium (IS: 0.070.0) (Po0.001) (Table 2). The rate of
high cytoplasmic expression (IS43) was zero in
normal epithelium (0/29) and CIN I/II (0/3 and 0/8),
but significantly increased in CIN III (7/23, 30%)
and carcinoma (8/36, 22%) (Po0.01) (Table 3).
The nuclear expression of Gli-1 was very weak
and rare in normal cervical epithelium (Figures 1
and 2). The average intensity of nuclear expression
significantly increased in CIN II (IS: 2.372.3)/CIN
III (IS: 1.471.5) and carcinoma (IS: 1.071.3),
compared with in normal epithelium (IS: 0.170.3)
(Po0.001) (Table 2). The rate of high nuclear
expression (IS43) was generally low in overall
cervical lesions without a significant difference
The cytoplasmic expression of Gli-2 was completely
absent in normal epithelium, but aberrant
expression of the protein was frequently noted in CIN II/III
and carcinoma in the same manner as in Gli-1
(Figures 1 and 2). The average intensity of
cytoplasmic Gli-2 expression significantly increased in CIN
II (IS: 1.171.4)/CIN III (IS: 1.171.2) and carcinoma
(IS: 1.171.3), compared with in normal epithelium
(IS: 0.070.0) (Po0.001) (Table 2). The rate of high
cytoplasmic expression (IS43) was generally low in
overall cervical lesions without a significant
difference (Table 3).
The nuclear expression of Gli-2 was very abundant
in normal epithelium in contrast to cytoplasmic
staining (Figure 1). Nuclear staining was also found
in endocervical glands as well as squamous
epithelium. The average intensity of nuclear expression
significantly increased in CIN I (IS: 6.871.0)/CIN II
(IS: 7.771.4)/CIN III (IS: 8.272.3) and carcinoma (IS:
8.272.4) (Po0.001), compared with in normal
epithelium (IS: 4.971.6) (Table 2). The rate of high
nuclear expression (IS47) was low in normal
epithelium (3/29, 10%), but significantly increased
in CIN II/III (5/8, 63% and 16/22, 73% respectively)
and carcinoma (26/38, 68%) (Po0.001) (Table 3).
In contrast to Gli-1/2, the majority of Gli-3
expression was cytoplasmic. The nuclear expression was
observed in only three cases out of 36 carcinomas.
There was no nuclear expression in the normal
epithelium and CIN I/II/III lesions (Figure 1).
Conversely, the cytoplasmic expression of Gli-3
was relatively abundant in normal epithelium.
Cytoplasmic staining was also focally found in
endocervical glands as well as in squamous
epithelium. The average intensity of cytoplasmic
expression was significantly increased in CIN II (IS:
4.172.0)/CIN III (IS: 5.672.0) and carcinoma
(IS: 5.872.1), compared with normal epithelium
(IS: 0.870.9) (Po0.001) (Table 2). And the average
intensity of Gli-3 cytoplasmic expression in
carcinoma was significantly higher than in CIN I/II
(Po0.05). On the other hand, the rate of high
cytoplasmic expression (IS43) was zero in normal
epithelium (0/25, 0%), but significantly increased in
CIN II/III (5/8, 63% and 18/22, 82%, respectively)
and carcinoma (30/36, 83%) (Po0.001) (Table 3).
In this study, we characterized the expression
pattern of Hh-signaling molecules via
immunohistochemistry in squamous cell carcinoma of uterine
cervix and its precursor lesions. Our results are
summarized in Table 3 and indicate that the
expression of Hh-signaling molecules is greatly
enhanced over the whole normal epithelium-CIN I/
II/III-carcinoma sequence in the uterine cervix. To
the best of our knowledge, this is the first study of
expression of Hh-signaling molecules in carcinoma
and CIN of uterine cervix. The expression of all
Hhsignaling molecules is upregulated in neoplastic
lesions including CIN and carcinoma, compared
with normal epithelium. The expression of Ihh,
PTCH, Smo, and Gli-1 was completely absent or rare
in normal epithelium, whereas frequent and
aberrant expression of these molecules was observed in
neoplastic lesions. These results strongly suggest
that the Hh-signaling pathway was extensively
activated in carcinoma and CIN of uterine cervix.
There has been no study regarding the expression
of Hh-signaling molecules in uterine cervix. The
significance and functional implication of the
Hhsignaling pathway in normal uterine cervical
epithelium are unknown. Based on our results, it is
postulated that the Hh?Gli-signaling pathway is
not functioning in normal cervical epithelium
despite the prevalent expression of Shh and
Gli2,3 because of absence or very rare expression of
PTCH and Smo, which are major mediators in the
Hh signaling. Instead, it is possible that Shh may
affect other uncharacterized signaling pathways
rather than the Shh?Gli pathway, and Gli-2 may
also be regulated by other signaling pathways such
as fibroblast growth factor (FGF) signaling2 in
normal cervix. The functional significance of Gli-3
as a transcription factor is questionable because its
expression was relatively restricted to the cytoplasm
instead of nucleus.
In the neoplastic lesions, the expression of PTCH
and Smo were dramatically increased. Thus, it can be
postulated that the Hh?Gli pathway is established.
The significance of the Hh-signaling pathway in
neoplastic lesions of uterine cervix is still elusive.
Generally, the Hh-signaling pathways are known to
function postembryonically in stem cell renewal,
tissue repair, and regeneration. When aberrantly and
persistently activated by chronic tissue injury, this
pathway may play an important role in the initiation
and growth of cancer.1 Hence, the Hh-signaling
pathway as well as WNT signaling can be considered
as a potential link between chronic tissue injury
and cancer. The first link between Hh signaling
and tumor formation was noted in patients with a
familial cancer syndrome, basal cell-nevus syndrome
(Gorlin?s syndrome) that is associated with a PTCH
mutation.2 Familial PTCH mutations that activate the
Hh pathway have been associated with an increased
incidence of cancers in brain, skin, skeletal muscle in
humans and mice. Additional studies in which the
Hh pathway activities were antagonized by drugs
such as cyclopamine, antibodies, and overexpression
of negatively acting pathway components
demonstrated an ongoing requirement for the Hh pathway
activity in small cell lung cancer and carcinomas of
esophagus, stomach, pancreas, colon, biliary tract,
and prostate.1 In addition, a consistent expression of
Gli2 and Gli3 was observed in breast carcinomas.2 It
is intriguing that the Hh pathway activation in tissues
that gives rise to non-Gorlin?s tumors seems to be
limited not by the ligand availability but by the
responsiveness to the ligand. In normal prostate, the
limiting factor for ligand responsiveness is Smo,
which is not expressed in normal prostate tissue, and
high-level activation of Hh pathway mediators
including Smo occurs only in cancer cells.
Collectively, these results are highly consistent with our
An important factor in the carcinogenesis of
uterine cervix is HPV infection, especially in
highrisk groups. E6 proteins derived from high-risk HPV
(type 16, 18, or 31) inactivate p53 by enhancing its
degradation through ubiquitin-dependent
proteolysis.19 It is intriguing that the hyperactivation of Hh?
Gli signaling synergizes with loss of other tumor
suppressor genes, especially p53. In other words,
tumorigenesis in the Ptc ? / mice was greatly
enhanced in a p53-null background.20 Therefore,
exaggerated and inappropriate activation of the
Hhsignaling pathway and inactivation of p53 by E6
proteins from the HPV may exert a synergistic effect
on the carcinogenesis of uterine cervix.
Previously we observed a two-fold increase of Shh
in gastric cancer.21 Shh expression is increased
twofold over the whole metaplasia?dysplasia early and
advanced gastric carcinoma. The first increase was
observed in metaplasia?dysplasia (adenoma)
transition. The second occurred during the progression of
early gastric cancer to advanced gastric cancer. This
expression pattern is very similar to that observed in
cervical neoplasia. The implications of these
findings remain to be clarified. However, these results
indicate that the role of Shh may change in a
dosagedependent manner and acquire additional
tumorpromoting functions at higher expression.
LOH at the PTCH locus was detected in 15.6% of
squamous cell carcinoma cases (5/32) of uterine
cervix.22 LOH, as well as an elevation of mRNA level
of PTCH was found in basal cell carcinoma (BCC).
This indicates that constitutive activation of Shh?
PTCH signaling is required for the development of
BCC.23 It was reported that PTCH ? / mice have a
higher incidence of squamous cell carcinomas after
ultraviolet (UV) exposure, and the size of the tumor
is also greatly increased.24 Therefore, it is possible to
postulate that genetic alteration or deregulation of
the expression of PTCH superimposed with another
genetic alteration such as UV exposure or p53
alteration by HPV may play a role in the
development of squamous cell carcinoma of uterine cervix.
Gli-1 is known to function primarily as an
oncogene if tumors arise due to overexpression.
However, Gli-2 and Gli-3 could function either as
oncogenes or tumor suppressors, depending on the
type of mutation and cellular context.6 However,
Gli-2 is known to have a redundant function with
Gli-1 and has been implicated in tumorigenesis.2
According to our results, Gli-2 may play a more
important role than Gli-1. The Gli-1 expression in
the nucleus is relatively frequent but is negative
in a considerable portion of tumor cases, whereas
nuclear expression of Gli-2 is strong and persistent
in all tumor cases. The nuclear expression of Gli-3 is
very rare in tumor cases. Thus, the role of Gli-3
as a transcription factor is considered minimal.
In summary, we demonstrated that the expression
of Hh-signaling molecules is greatly enhanced in
uterine cervical tumors including carcinoma and its
precursor lesions. Although the functional
significance of the Hh pathway remains to be determined
in uterine cervical cancer, the Hh-signaling pathway
may play an important role in tumorigenesis and
could be a potential therapeutic target.
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