Non-invasive diagnosis of early cutaneous squamous cell carcinoma

Early cutaneous squamous cell carcinoma (cSCC) can be challenging to diagnose using clinical criteria as it could present similar to actinic keratosis (AK) or Bowen's disease (BD), precursors of cSCC. Currently, histopathological assessment of an invasive biopsy is the gold standard for diagnosis. A non-invasive diagnostic approach would reduce patient and health system burden. Therefore, this study used non-invasive sampling by tape-stripping coupled with data-independent acquisition mass spectrometry (DIA-MS) proteomics to profile the proteome of histopathologically diagnosed AK, BD and cSCC, as well as matched normal samples. Proteomic data were analysed to identify proteins and biological functions that are significantly different between lesions. Additionally, a support vector machine (SVM) machine learning algorithm was used to assess the usefulness of proteomic data for the early diagnosis of cSCC. A total of 696 proteins were identified across the samples studied. A machine learning model constructed using the proteomic data classified premalignant (AK + BD) and malignant (cSCC) lesions at 77.5% accuracy. Differential abundance analysis identified 144 and 21 protein groups that were significantly changed in the cSCC, and BD samples compared to the normal skin, respectively (adj. p < 0.05). Changes in pivotal carcinogenic pathways such as LXR/RXR activation, production of reactive oxygen species, and Hippo signalling were observed that may explain the progression of cSCC from premalignant lesions. In summary, this study demonstrates that DIA-MS analysis of tape-stripped samples can identify non-invasive protein biomarkers with the potential to be developed into a complementary diagnostic tool for early cSCC.

Significant Role of Collagen XVII And Integrin β4 in Migration and Invasion of The Less Aggressive Squamous Cell Carcinoma Cells

Collagen XVII and integrin α6β4 have well-established roles as epithelial adhesion molecules. Their binding partner laminin 332 as well as integrin α6β4 are largely recognized to promote invasion and metastasis in various cancers, and collagen XVII is essential for the survival of colon and lung cancer stem cells. We have studied the expression of laminin γ2, collagen XVII and integrin β4 in tissue microarray samples of squamous cell carcinoma (SCC) and its precursors, actinic keratosis and Bowen's disease. The expression of laminin γ2 was highest in SCC samples, whereas the expression of collagen XVII and integrin β4 varied greatly in SCC and its precursors. Collagen XVII and integrin β4 were also expressed in SCC cell lines. Virus-mediated RNAi knockdown of collagen XVII and integrin β4 reduced the migration of less aggressive SCC-25 cells in horizontal scratch wound healing assay. Additionally, in a 3D organotypic myoma invasion assay the loss of collagen XVII or integrin β4 suppressed equally the migration and invasion of SCC-25 cells whereas there was no effect on the most aggressive HSC-3 cells. Variable expression patterns and results in migration and invasion assays suggest that collagen XVII and integrin β4 contribute to SCC tumorigenesis.

Expression of Endothelins and Their Receptors in Nonmelanoma Skin Cancers

Background:

Endothelins are paracrine peptides with growth-promoting and vasoactive functions for a variety of cell types. Elevated activation of the endothelin signaling pathway induces cell proliferation and/or survival and is implicated in a variety of malignancies. Increased endothelin 1 was described in solar lentigines in previous reports, raising the possibility that the endothelin pathway may be of significance in keratinocyte proliferation-related disorders. However, detailed investigation on endothelins in skin malignancies is lacking.

Objectives:

This study aims to survey the expression of endothelins and their receptors in keratinocyte-derived benign and malignant tumors of the skin and to test the effects of endothelin inhibitors on the growth and survival of cultured keratinocytes.

Methods:

Quantitative polymerase chain reaction was used to measure the level of gene transcription of three endothelins (ET-1, −2, and −3) and two endothelin receptors (ETRA and ETRB). The genes with significant messenger ribonucleic acid (mRNA) expression abnormalities were confirmed with immunohistochemical analysis to examine expression differences at the protein levels. To analyze the effect of endothelin inhibitors on the keratinocyte growth and survival, keratinocytes were cultured in the presence of various concentrations of endothelin inhibitors and subjected to tetrazolium bromide assay to quantify the cell numbers over time.

Results:

ET-1 mRNA was found to be significantly up-regulated in seborrheic keratosis and basal cell carcinoma. However, no significant expression increase was found in actinic keratosis, Bowen's disease, or squamous cell carcinoma. Immunohistochemical analysis of ET-1 peptide confirmed increased expression. In cultured keratinocytes, peptide inhibitors of the endothelin pathway resulted in a marked reduction in cell survival.

Conclusion:

The endothelin signaling pathway, especially ET-1, is activated in basoloid keratinocyte neoplasms of the skin, such as basal cell carcinoma and seborrheic keratosis. Blockade of this pathway can reduce cell survival in vitro. Therefore, endothelin inhibitors potentially offer a novel method for the treatment of some keratinocyte-derived skin tumors.

Role of mitochondria, ROS, and DNA damage in arsenic induced carcinogenesis

The International Agency for Research on Cancer (IARC) declared arsenic a class I carcinogen. Arsenic exposure induces several forms of human cancers, including cancers of skin, lung, liver, and urinary bladder. The majority of the arsenic-induced cancers occur in skin. Among these, the most common is Bowen's disease, characterized by epidermal hyperplasia, full layer epidermal dysplasia, leading to intraepidermal carcinoma as well as apoptosis, and moderate dermal infiltrates, which require the participation of mitochondria. The exact mechanism underlying arsenic induced carcinogenesis remains unclear, although increased reactive oxidative stresses, leading to chromosome abnormalities and uncontrolled growth, and aberrant immune regulations might be involved. Here, we highlight how increased mitochondrial biogenesis and oxidative stress lead to mitochondrial DNA damage and mutation in arsenic induced cancers. We also provide therapeutic rationale for targeting mitochondria in the treatment of arsenic induced cancers.

[Expression of promyelocytic leukaemia protein in Bowen's disease, skin squamous cell carcinoma and basal cell carcinoma]

OBJECTIVE

To investigate the expression of promyelocytic leukaemia (PML) protein of PML protein in Bowen's disease (BD), skin squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) and explore the role of PML in the pathogenesis of these diseases.

METHODS

PML protein in normal skin tissues and lesions of Bowen's disease, SCC and BCC were detected with immunohistochemistry.

RESULTS

Normal skin tissues did not express PML protein. In BCC, PML showed rather low expressions in the skin lesions (8.69% in cell nuclei and 4.35% in cytoplasm). The lesions in BD and SCC (grade I and II) showed obvious overexpression of PML protein in the cell nuclei and cytoplasm, and its expression in the cell nuclei of these lesions was significantly higher than that in grade III-IV SCC.

CONCLUSION

PML protein may play an important role in the early stage of SCC, and its overexpression may contribute to the carcinogenesis and metastasis of SCC.

Nuclear translocation of ATBF1 is a potential prognostic marker for skin cancer

The AT motif binding factor 1 (ATBF1) is expressed in various tissues, such as brain, liver, lung, and gastrointestinal tract, and has an important role in cell differentiation in organs. ATBF1 interacts with PIAS3, a protein inhibitor for activated signal transducer and activator of transcription (STAT3), to suppress STAT3 signaling, which has critical roles in cell proliferation, migration, and survival. We hypothesized that ATBF1 is a useful prognostic marker for skin cancer. We performed immunohistochemical analyses of squamous cell carcinoma (SCC, n=7), basal cell carcinoma (BCC, n=4), and Bowen's disease (n=4) tissues using an anti-ATBF1 monoclonal antibody. All cases of BCC and Bowen's disease exhibited intense nuclear ATBF1 staining, whereas only some SCC cases exhibited weakly positive nuclear ATBF1 staining. SCC and Bowen's disease showed intense nuclear STAT3 staining, while BCC had few STAT3-positive nuclei. Based on these observations, nuclear ATBF1 staining was associated with low malignancy profiles. The pattern of ATBF1 staining is a potential prognostic marker for skin cancer.

CCR10 and CCL27 are overexpressed in cutaneous squamous cell carcinoma

C-C chemokine receptor (CCR)10 is a specific receptor for chemokine ligand (CCL)27, a selective chemoattractant for skin-associated memory T cells to cutaneous sites. In melanoma, CCR10 increases the ability of neoplastic cells to grow, invade tissues, disseminate to lymph nodes, and escape the host immune responses. In this study, we investigated the expression of CCR10 and its ligand CCL27 in squamous cell carcinoma (SCC). CCR10 and CCL27 were expressed in SCC, actinic keratosis (AK), Bowen's disease, and seborrheic keratosis (predominantly prickle cell type), but not in seborrheic keratosis (predominantly basal cell type) and basal cell carcinoma. Furthermore, CCR10 and CCL27 were overexpressed in SCC relative to Bowen's disease, an early stage of SCC. Consistently, a human SCC cell line, A253 cells, and HaCaT cells exhibited CCL27 production that was strongly induced by tumor necrosis factor-α and interleukin-1β. Finally, A253 cells expressed stronger intracellular CCR10 compared to HaCaT cells by flow cytometry. These results suggest that CCR10 and CCL27 overexpression in SCC is related to the progression of SCC and is useful for the diagnosis of SCC.

Expression of P27, Ki67 and P53 in squamous cell carcinoma, actinic keratosis and Bowen disease

This study aims at evaluating the expression of P27, Ki67 and P53 in Squamous Cell Carcinoma (SCC), Actinic Keratosis (AK) and Bowen Disease (BD) specimens. In an analytic-descriptive setting, skin biopsy specimens of 45 patients were evaluated in three 15-case groups including BD, AK and SCC specimens. Fifteen normal skin biopsy specimens were obtained and used as the control group. Immunohistochemical staining was performed in all the specimens and the expression rates and patterns of Ki67, P27 and P53 were determined. The results were compared between the four groups. Ki67 was expressed in 0.8, 23.7, 12.3 and 19.3% of the cells in the normal skin, AK, BD and SCC groups, respectively. No significant difference was seen between the three pathological conditions regarding the expression rate of Ki67. P27 was positive in 23.4, 26.2, 25.9 and 4.5% of specimens in the normal skin, AK, BD and SCC groups, respectively. This rate was significantly the lowest in the SCC group. P53 expression was detected in 26.6, 41.8 and 54.6% of the assessed cells in the AK, BD and SCC groups, respectively. There was no expression of P53 in the normal skin specimens. This rate was significantly the highest again in the SCC group. Based on these results, the quantitative and qualitative (pattern of distribution) evaluation of the expressions of Ki67, P27 and P53 may be helpful in differentiating malignant and premalignant epidermal lesions, particularly in unsatisfactory or fragmented specimens.

[The expressions of PPAR-gamma, COX-2 in the lesions of patients with condyloma acuminatum and bowenoid papulosis]

OBJECTIVE

To investigate the expression of PPAR-gamma, COX-2 in the skin lesion of condyloma acuminatum and bowenoid papulosis.

METHODS

The expression levels of PPAR-gamma, COX-2 were measured by immunohistochemistry in 17 cases of condyloma acuminatum, 17 cases of bowenoid papulosis, as well as 17 cases of normal foreskin lesions.

RESULTS

The immunohistochemical study showed that PPAR-gamma and COX-2 weakly expressed in normal foreskin, but overexepressed in the skin lesions of both condyloma acuminatum and bowenoid papulosis (P<0.01). There was straight linear correlation between the expressions of PPAR-gamma and COX-2 not only in condyloma acuminatum (r=0.505, P=0.038) but also in bowenoid papulosis (r=0.562, P=0.019).

CONCLUSION

PPAR-gamma and COX-2 may have important roles in proliferative dermatosis associated with human papilloma virus.

Prevalence of Foxp3 positive T regulatory cells is increased during progression of cutaneous squamous tumors

PURPOSE

Forkhead box p3 (Foxp3) positive T regulatory cells (Tregs) have a functionally immunosuppressive property that prevents effector cells from acting against self in autoimmune diseases or a tumor. It is known that Tregs may be highly relevant in cancer progression. Dendritic cells (DCs) induce cutaneous immune response, however several studies have suggested that DCs are involved in immunosuppression. The aim of this study is to evaluate the prevalence of Tregs and DCs infiltration in cutaneous premalignant and malignant squamous lesions.

MATERIALS AND METHODS

We evaluated Tregs and DCs in skin tissue samples obtained from 83 patients with actinic keratosis, Bowen's disease or squamous cell carcinoma by immunohistochemistry.

RESULTS

The prevalence of Tregs and DCs was significantly higher in squamous cell carcinoma and Bowen's disease than in actinic keratosis. In addition, the number of DCs was closely correlated with the prevalence of Tregs, and DCs were also located in direct proximity to Tregs.

CONCLUSION

Tregs is related to cutaneous squamous tumor progression.

Expression of p63 and cyclooxygenase-2 and their correlation in skin tumors

To study the expression of p63 and cyclooxygenase-2 (cox-2) in skin tumors and evaluate the correlation between p63 and cox-2, the expressions of cox-2 and p63 were measured by streptavidin-peroxidase complex immunohistochemical technique in 17 cases of skin squamous cell carcinoma (SCC), 19 cases of Bowen's disease(Bowen), 11 cases of actinic keratosis(AK), 12 cases of seborreic keratosis(SK) and 13 specimens of normal skin. Our results showed that the expression of p63 in skin squamous cell carcinoma, Bowen's disease and actinic keratosis were significantly higher than that in seborreic keratosis, while the expression of p63 in seborreic keratosis was significantly higher than that in normal skin. The expression of cox-2 in skin squamous cell carcinoma, Bowen's disease and actinic keratosis were significantly higher than that in seborreic keratosis, while no statistical difference was noted in the expression of cox-2 between seborreic keratosis and normal skin. Cox-2 expression was positively correlated with the high p63 expression in malignant skin tumors. The increased expression of cox-2 and p63 may play an important role in the development of skin tumors and work synergetically in malignant skin tumors.

Assessment of Cell Proliferation in Benign, Premalignant and Malignant Skin Lesions

A deeper understanding of the variance of epidermal cell proliferation may eventually increase the reproducibility of diagnostic classification. A prospective study of 46 consecutive, unselected biopsies from benign (keratoacanthoma n=14), premalignant (actinic keratosis n=15 and Bowen disease n=10) and malignant (squamous cell carcinoma n=7) skin lesions was studied to assess the presence and extent of differences in expression of the proliferation marker Ki-67 using a monoclonal antibody directed against a c-DNA defined subsegment (MIB-1) and a noncross-linking, proprietary fixative BoonFix. MIB-1 was expressed in the adjacent, non-affected skin in a scattered to confluent linear pattern in the basal/suprabasal cell layer. In actinic keratosis, MIB-1 expression, in addition to basal/suprabasal layers, extended to mid-zones of the epidermis. An interesting feature in actinic keratosis as well as in Bowen disease was the expression of MIB-1 in the epithelium lining the hair follicles. In Bowen disease, MIB-1 was observed throughout the full thickness of the epidermis, unequivocally separating this entity from others under study. In invasive squamous cell carcinoma, MIB-1 expression was not consistent between and within cases. MIB-1 positivity was variably found in all layers of the epidermis, but showed a chaotic and haphazard pattern with total loss of polarity. Keratoacanthoma cases showed highly variable MIB-1 expression, ranging from no expression to expression in both basal/suprabasal and mid-zone layers of the epidermis. These results warrant further study of modulation of cell proliferation in actinic keratosis.

Cancer/testis antigen MAGE-A4 expression pattern differs in epithelial skin tumors of organ-transplant recipients and immunocompetent patients

BACKGROUND

Lifetime risk for squamous cell carcinoma (SCC) of the skin is 1:30. Risk in organ-transplant recipients (OTR) is increased over 60-fold through long-term drug-induced immunosuppression. MAGE family-derived peptides are cancer/testis antigens recognized by specific CD8(+) T cells and employed for immunotherapy. We were interested in the frequency and distribution of MAGE-A4 in epithelial skin tumors of OTR and immunocompetent patients.

METHODS

mAb 57B predominantly recognizing MAGE-A4 was used to stain 119 formalin-fixed, paraffin-embedded epithelial skin tumors (actinic keratosis, bowenoid actinic keratosis, Bowen's disease, and SCC; n = 17, 25, 61, 16, respectively) in immunocompetent patients (n = 84) and OTR (n = 35).

RESULTS

All four epithelial skin tumors showed comparable immunoreactivity ranging from (25-71%, p = 0.361). Scattered immunoexpression pattern was more frequent in OTR (p = 0.025). SCC showed polarized immunoreactivity basally (p = 0.002).

CONCLUSION

MAGE-A4 was expressed in a large part of epithelial skin tumors with predominantly scattered immunoexpression pattern in OTR. The difference in immunoexpression pattern for immune status was limited, suggesting important non-immunosuppressor-mediated mechanisms for increased skin carcinogenesis in OTR. mAb 57B may be a helpful tool for immunohistochemistry and micrographic surgery using formalin-fixed paraffin-embedded tissue.

Strong expression of a longevity-related protein, SIRT1, in Bowen's disease

The class III histone deacetylase (HDAC), SIRT1, is a mammalian homologue of the Saccharomyces cerevisiae chromatin-silencing factor Sir2 that regulates longevity. SIRT1 regulates cell survival via deacetylation of p53 and forkhead transcription factors, and overexpression of SIRT1 is reported to be essential for cell growth and survival in some kinds of cancer. To elucidate the role of SIRT1 in human skin carcinogenesis, we have examined SIRT1 protein expression in 20 cases each of squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease (BD), and actinic keratosis (AK) by immunohistochemical analysis. Overexpression of SIRT1 is frequently observed in all kinds of non-melanoma skin cancers included in this study. In particular, strong expression was observed in all cases of BD. In addition, no obvious difference between AK and SCC was observed in the expression of SIRT1, suggesting that overexpression of SIRT1 may have some relevance to the early stage of skin carcinogenesis. We suppose that SIRT1 could be one of the critical targets for future therapy with the aim of inhibiting cell proliferation and promoting apoptosis in non-melanoma skin cancers.

P16(INK4A) expression in Bowen's disease and Bowenoid papulosis

BACKGROUND

Bowen's disease (BD) is a skin carcinoma in situ occurring over the entire body surface. It shares similar histopathological features with Bowenoid papulosis (BP) of the genitalia, but differs in etiology and clinical course. Increased p16(INK4A) (p16) tumor suppressor protein expression has been demonstrated in relation to the progression of cutaneous squamous neoplasms.

OBJECTIVE

To evaluate the difference in p16 expression between Bowen's disease and Bowenoid papulosis.

MATERIAL AND METHOD

Biopsies of 46 cases of BD in the period 1994 - 2003 and 14 cases of BP during 1987 - 2003 in the Anatomical Pathology Unit, Department of Pathology, Faculty of Medicine, Prince of Songkla University, Thailand were studied by immunohistochemical methods using the P16 kit (CINTec Histology Kit, clone E6H4, Code-Nr. K5334, DakoCytomation, Denmark). Nuclear/cytoplasmic immunoreactivity in more than 10% of neoplastic cells was considered positive.

RESULTS

P16 expression was positive in 37 of 46 BD cases (80.4%) which was higher than that of BP (6 of 14 cases or 42.9%) (p value < 0.05, Chi-square test). The expression among the three groups of BD: extragenital (28 of 35), chronic arsenical-related (7 of 8) and genital lesions (2 of 3) was not significantly different (p value = 0.734, Chi-square test).

CONCLUSION

P16 expression was more frequent in BD than BP. This suggests a possible association between p16 expression and tumorigenesis of these lesions.

Correlation of p16 and pRb expression with HPV detection in Bowen's disease

BACKGROUND

Bowen's disease is a form of cutaneous squamous cell carcinoma which may be caused by ultraviolet radiation, human papilloma virus (HPV) infection, or other causes. Although p16 over-expression is a surrogate marker of HPV E7-mediated catabolism of pRb in premalignant and malignant lesions of the cervical mucosa, the correlation of p16 and pRb expression with HPV detection in Bowen's disease has not been well characterized.

METHODS

A retrospective study on formalin-fixed tissues was performed. Immunohistochemistry for p16 and pRb was performed on 32 cases. DNA was successfully extracted from 20 cases, and polymerase chain reaction was performed to amplify a highly conserved region of the HPV L1 open reading frame.

RESULTS

Twenty-eight of 32 (88%) cases showed strong diffuse staining for p16 but were negative for pRb; two of 32 cases (6%) were negative for p16 but were diffusely positive for pRb; one case was strongly positive for both p16 and pRb, and one case was negative for both p16 and pRb. Three of 20 cases (15%) contained HPV DNA. All three of these cases showed strong p16 expression and lack of pRb staining.

CONCLUSIONS

Most cases of Bowen's disease strongly express p16 but not pRb. In contrast to HPV-associated lesions of the cervical mucosa, p16 overexpression in cutaneous Bowen's disease appears to be unrelated to HPV status. The p16 overexpression in Bowen's disease may reflect disruption of the G1/S checkpoint, resulting in unregulated cell cycle progression.

DNase1L2 degrades nuclear DNA during corneocyte formation

The removal of keratinocyte (KC) nuclear DNA by deoxyribonucleases (DNases) is an important step in the formation of normal stratum corneum (SC). However, the molecular identity of the DNA-degrading enzymes has so far remained elusive. Here we show that the endonuclease DNase1-like 2 (DNase1L2) is preferentially expressed in the epidermis and that its expression correlates with terminal differentiation of KC in vitro and in vivo. In biopsies of normal skin, DNase1L2 mRNA was regularly found in suprabasal KC and DNase1L2 protein was highly abundant in the stratum granulosum. In contrast to normal skin, DNase1L2 expression was downregulated in parakeratotic epidermis such as in psoriatic lesions. When DNase1L2 gene expression was knocked down by small interfering RNA in a human skin equivalent model, nuclei were maintained through all layers of the SC. Taken together, our data demonstrate that DNase1L2 plays an essential role in DNA degradation during terminal differentiation of epidermal KC.

[Expression of E-cadherin and beta-catenin in Bowen's disease and squamous cell carcinoma]

OBJECTIVE

To investigate the involvement of E-cadherin-catenin adhesion system in Bowen's disease (BD) and cutaneous squamous cell carcinoma (SCC).

METHODS

Fifteen normal skin, 28 BD and 18 SCC specimens were stained with monoclonal antibodies against E-cadherin and beta-catenin. Evaluation of the staining results was performed with semi-quantification of the pattern and intensity of staining, percentage of positive cells, and cytoplasmic staining.

RESULT

Normal skins strongly expressed membranous E-cadherin and beta-catenin, but their expression was remarkably reduced in BD and SCC. Abnormal staining of beta-catenin was observed in the cytoplasm or cell nuclei of BD and SCC.

CONCLUSION

Abnormal expression of the E-cadherin/catenin complex is common in SCC and BD.

Immunohistochemical study of cyclooxygenase-2 and p53 expression in skin tumors

Overexpression of cyclooxygenase-2 (COX-2) has been demonstrated in various cancers, including experimentally promoted tumors, gastrointestinal cancers, breast tumors and skin tumors. The mechanism that controls COX-2 expression is not yet clear. Currently, it is reported that COX-2 expression is frequently associated with mutated p53 genes. The goal of this study was to evaluate the expression patterns of COX-2 and p53 in several skin tumors and their correlation. An immunohistochemical method was used to investigate the expression of COX-2 and p53 proteins on formalin-fixed, paraffin-embedded tissue specimens of squamous cell carcinomas (SCC), basal cell carcinomas (BCC), Bowen's disease (BD), actinic keratosis (AK) and porokeratosis. The expression of COX-2 increased in 50% (5/10) of SCC, 80% (8/10) of BCC, 40% (4/10) of BD, 50% (5/10) of AK, and 20% (2/10) of porokeratosis cases. The expression of p53 increased in 90% (9/10) of SCC, 70% (7/10) of BCC, 70% (7/10) of BD, 50% (5/10) of AK, and 40% (4/10) of porokeratosis cases. COX-2 positivity rates of the p53-positive skin tumors were 56%, 100%, 57%, 80% and 25% in SCC, BCC, BD, AK and porokeratosis, respectively. However, the correlation between p53 and COX-2 expression in skin tumors was not statistically significant (P > 0.05). Our results indicate that skin COX-2 and p53 may play roles in skin tumors, but that there is no apparent correlation between the two markers.

Cyclin A and beta-catenin expression in actinic keratosis, Bowen's disease and invasive squamous cell carcinoma of the skin

BACKGROUND

Actinic keratosis (AK) has been defined as a precancerous lesion or an early phase in the evolution of squamous cell carcinoma (SCC) and histological changes seen in the individual cells of an AK are indistinguishable from those seen in SCC, which invade the dermis. Cyclin A is an increasingly utilized proliferation marker that has functions in both S phase (DNA replication) and initiation of mitosis, whereas alterations of beta-catenin, the molecule involved in cell-cell adhesion and in signalling transduction, could promote invasive and proliferative capacities of malignant tumours.

OBJECTIVES

To determine cyclin A and beta-catenin expression pattern in cutaneous SCC and in in situ lesions classified as keratinocytic intraepidermal neoplasia (KIN) and, using traditional terms, as AK and Bowen's disease (BD), and to analyse it in relation to SCC differentiation, diameter and thickness.

METHODS

Immunohistochemical staining was performed on 110 formalin-fixed paraffin-embedded tissue samples with the streptavidin-biotin technique using antibodies to cyclin A and beta-catenin. On histological examination, 53 lesions were diagnosed as AK, 16 as BD and 41 as SCC-11 well differentiated (WD), 16 moderately differentiated (MD) and 14 poorly differentiated (PD). Using KIN classification, 22 lesions were KIN1, 23 were KIN2 and 24 were KIN3. For cyclin A, distribution and labelling index (LI), and for beta-catenin, level of membranous staining and presence of aberrant (nuclear/cytoplasmic) localization were examined.

RESULTS

Diffuse cyclin A presence was observed more frequently in BD than in AK (P < 0.0001) or SCC (P = 0.0002), and in SCC-PD compared with SCC-WD (P < 0.0001) or SCC-MD (P = 0.0003). Differences between KIN3 and KIN2, as well as KIN3 and KIN1 lesions, were statistically significant (P < 0.0001), and the same result appeared when KIN1 and KIN2 cases were grouped and compared with those of KIN3 (P < 0.0001). Cyclin A LI was significantly lower (P < 0.05) in AK than in BD or SCC, but no difference between BD and SCC was found, and LI in BD was even higher than in SCC-WD or SCC-MD, while analysis regarding SCC differentiation and KIN classification revealed the same correlation as for the cyclin A distribution. Reduced or absent beta-catenin membranous staining was found in 90 cases (81.8%), more often in SCC than in AK (P = 0.03) or in AK and BD grouped together (P = 0.02). There was no statistical difference between SCCs of various level of differentiation, or between different KIN grades. Diffuse loss of membranous beta-catenin staining showed 36 lesions (32.7%), more frequently SCC than AK (P = 0.003) or AK and BD grouped (P = 0.006), as well as SCC-PD compared with SCC-WD (P = 0.01) and SCC-MD (P = 0.03), whereas all KIN comparisons remained nonsignificant. Aberrant beta-catenin cellular localization demonstrated 28 lesions (25.5%), most often in the basal or peripheral parts and in the lesions with diffuse beta-catenin loss (P = 0.009), but revealed no correlation with the histological type, SCC level of differentiation or KIN grades. Diffuse loss of membranous beta-catenin staining was found to be significantly more frequent in SCC thicker than 4 mm (P = 0.03), while all other comparisons between cyclin A or beta-catenin with the tumour size remained nonsignificant. Cyclin A LI was higher in cases with diffuse loss of membranous staining (P = 0.001) or with aberrant cellular localization of beta-catenin (P = 0.002).

CONCLUSIONS

Cyclin A LI showed greater difference between AK and BD than between BD and SCC, suggesting that increased proliferation (measured by cyclin A LI) characterizes progression of in situ lesions from AK to BD, whereas reduced beta-catenin expression separates more clearly SCC from the in situ lesions. Diffuse pattern of loss of membranous beta-catenin staining correlated better with the type of lesion, SCC differentiation and tumour size than reduced expression in general or aberrant cellular localization of beta-catenin. KIN classification does not seem to be supported by our findings, except when KIN1 and KIN2 lesions (in situ, partial thickness) are grouped.

Differential induction of connexins 26 and 30 in skin tumors and their adjacent epidermis

Gap junctions (GJs) have been shown to play a role in tumor progression including a variety of keratinocyte-derived and non-keratinocyte-derived skin tumors. Here we show that the synthesis of the GJ proteins connexin 26 and connexin 30 (Cx26 and Cx30) is induced in keratinocyte-derived epithelial skin tumors whereas there is either no change or a downregulation of Cx43. Cx26, Cx30, and Cx43 are absent in non-epithelial skin tumors. Further, Cx26 and Cx30 are induced in the epidermis adjacent to malignant melanoma but absent in the epidermis adjacent to benign non-epithelial skin lesions (melanocytic nevi and angioma). The keratinocyte-derived skin tumors are very heterogeneous regarding the Cx26/Cx30 pattern in the epidermis at the periphery of the tumors. We did not observe any difference in the localization of the very similar proteins Cx26 and Cx30 but a variation in intensity of immunoreactivity. As the staining patterns of Cx26 and Cx30 antibodies are not identical to those of CK6, a marker for hyperproliferation, and CK17, a marker for trauma, we discuss that the induction of these gap junctional proteins exceeds a reflection of reactive hyperproliferative or traumatized epidermis. We further discuss the putative roles of these gap junctional proteins in tumor progression.

Bowen's disease on the sole: p16INK4aoverexpression associated with human papillomavirus type 16

We report a case of Bowen's disease on the sole presenting clinically as an exophytic, blackish-grey, verrucous tumour, and showing human papillomavirus (HPV) type 16 on analysis with polymerase chain reaction. Positive stains for HPV particles by immunohistochemical analysis were limited to several cell nuclei at the upper stratum Malpighii. However, all the tumour cells in the epidermis exhibited strong and diffuse nuclear and cytoplasmic stains for the tumour suppressor protein p16INK4a. We speculate that dysregulation of the retinoblastoma/p16INK4a pathway may be involved in the pathogenesis of the lesion, and p16INK4a overexpression might serve as a useful surrogate marker for identifying Bowen's disease harbouring high-risk types of HPV infection.

Expression and glycosylation of MUC1 in epidermolysis bullosa-associated and sporadic cutaneous squamous cell carcinomas

BACKGROUND

Cutaneous squamous cell carcinoma (SCC) is particularly problematic in certain patient groups, including patients with dystrophic or junctional epidermolysis bullosa (DEB/JEB). Theoretically, vaccination against a cell surface antigen which is expressed on this type of tumour could prevent SCC development, as well as treat primary and metastatic disease in this patient group. Preliminary studies have suggested that MUC1, a transmembrane glycoprotein, is overexpressed in sporadic cutaneous SCCs, and MUC1 has been used with some success as a target antigen for vaccine development in breast cancer, where it is expressed on > 50% of neoplastic cells in approximately 50-80% of tumours. Furthermore, aberrant glycosylation of MUC1 has been detected in this and other cancer types; however, the glycosylation status of MUC1 in cutaneous SCC is not known.

OBJECTIVES

To investigate the expression and glycosylation status of MUC1 in SCCs arising in patients with DEB and JEB, and for comparison in sporadic SCCs and sporadic Bowen's disease.

METHODS

Immunohistochemical analysis of MUC1 in 30 SCCs from subjects with DEB/JEB, 55 sporadic SCCs and 30 sporadic lesions of Bowen's disease was carried out using four separate monoclonal antibodies which recognize different isoforms of MUC1.

RESULTS

Expression of MUC1 was detected in 100% of SCCs arising in patients with DEB and JEB; > 50% of neoplastic cells stained positive for MUC1 in 57% of DEB/JEB SCCs, with over 95% of tumour cells immunopositive in 33% of cases. MUC1 expression was also observed in 95% of sporadic SCCs and 97% of Bowen's disease, with 36% of sporadic SCCs immunopositive for MUC1 in > 50% of tumour cells. Investigation of the glycosylation status showed that MUC1 was predominantly hyperglycosylated in the DEB/JEB and sporadic tumours.

CONCLUSIONS

The results demonstrate that a significant proportion of DEB/JEB and sporadic SCCs express MUC1 in > 50% of tumour cells. Therefore, MUC1 may be a suitable candidate antigen against which to develop a tumour vaccine for these patient groups.

The expression of p63 in actinic keratoses, seborrheic keratosis, and cutaneous squamous cell carcinomas

BACKGROUND

p63 is a tumor suppressor that likely plays a role in the development of squamous cell carcinomas (SCCs) and possibly premalignant and benign skin tumors. Little data is available on its expression in these tumors.

OBJECTIVE

To study the keratinocyte expression profile of p63 in 17 SCCs, 7 actinic keratoses, 2 Bowens tumors, and 7 seborrheic keratoses.

METHODS

Skin tumors specimens were stained with an antibody to p63. Quantitative and qualitative data was collected on the staining.

RESULTS

There was a statistically significant increase in p63 staining of SCCs when compared with normal. Seborrheic keratoses and actinic keratoses showed a trend towards increased expression in the basal layer compared with normal skin. The pattern of expression showed diffuse staining in SCCs. In actinic keratoses and seborrheic keratoses the pattern was most prominent in the basal layer.

CONCLUSIONS

p63 expression is greater and different in SCCs when compared with normal skin, actinic keratoses, and seborrheic keratoses. Interestingly seborrheic keratoses and Bowens lesions showed expression that was mostly restricted to the basal layer, however significant diffuse staining was also noted. Our results support the notion that p63 plays a role in cell differentiation and tumorigenesis of skin tumors.

Phosphorylation state of tumor-suppressor gene p53 product overexpressed in skin tumors

Post-transcriptional modification of p53 by phosphorylation has been proposed as an important mechanism of p53 stabilization and functional regulation. However, little is known about the phosphorylation state of mutant p53 protein overexpressed in human tumors. We evaluated immunohistochemically the p53 phosphorylation state of Ser392 and Ser15 sites in 44 actinic keratoses (AKs), 62 squamous cell carcinomas (SCCs), 23 Bowen's disease (BDs) and 43 basal cell carcinomas (BCCs). The mean labeling index (LI) of phospho-Ser392-p53 was significantly higher than that of phospho-Ser15-p53 in all cases. Phospho-Ser392-p53 protein was frequently overexpressed in not only SCCs but also AKs and BDs, revealing no significant difference in the immunoreactivity among them. In BCCs, phospho-Ser392-p53 immunoreactivity was significantly lower than that in BDs, and phospho-Ser15-p53 immunoreactivity was significantly lower than that in SCCs. Ser15 phosphorylation was significantly correlated with a high level of Ki-67 LI in BCCs. These results suggest that p53 overexpressed in skin tumors is more frequently phosphorylated at Ser392 residue than Ser15, and that the Ser392 phosphorylation is more likely to occur early in the pathogenesis of SCC. Moreover, the decreased level of the phosphorylation might be characteristic of BCC, but the Ser15 phosphorylation seems to have an influence on BCC development.

Eccrine porocarcinoma with Bowenoid changes: epithelial membrane antigen is not a useful marker for malignant tumours arising from eccrine gland structures

A case of eccrine porocarcinoma with Bowenoid changes is reported. We compared the results of immunohistochemical staining for epithelial membrane antigen in the present case with results in Bowen's disease to determine whether the presence of epithelial membrane antigen (EMA) enabled us to differentiate between Bowen's disease and eccrine porocarcinoma with Bowenoid changes. Histologically, the present tumour was characterized by atypical clear cells with Bowenoid changes as well as uniform small cells and intradermal nests with ductal structures. The membrane and cytoplasm of uniform small cells and ductal luminal surfaces were positive for EMA. However, the atypical cells with Bowenoid changes were negative for this. In contrast, tumour cells in Bowen's disease were positive for EMA. Although EMA is known to be a useful marker for some benign tumours derived from eccrine ducts, we found it difficult to distinguish eccrine porocarcinoma with Bowenoid changes from Bowen's disease using immunohistochemical staining for EMA.

Expression of desmosomal proteins in squamous cell carcinomas of the skin

BACKGROUND

Desmosomal proteins are well established markers of epithelial differentiation. Down-regulation of desmosomal proteins has been suggested to be a sign of reduced adhesiveness in metastasizing cells.

METHODS

We examined actinic keratoses, Bowen's disease, and squamous cell carcinoma (SCC) of the skin for the expression of desmosomal proteins using isoform-specific antibodies on paraffin-embedded sections. Evaluation was performed qualitatively in comparison to the epidermis and semiquantitatively using an area-intensity-score.

RESULTS

We found no qualitative correlation of desmoplakin or plakoglobin expression with risk of metastasis. Plakophilin 1, desmoglein 1, and the desmocollins 1-3 were found to be heterogeneously expressed in all neoplasms without significant correlation to aggressive tumor behavior. Plakophilin 2 was not expressed in any of the neoplasms examined. As most striking finding, desmoglein 2 was up-regulated qualitatively in half of all neoplasms examined and showed a significant higher proportion of positive cells in high-risk SCC than in low-risk SCC.

CONCLUSIONS

Desmosomal proteins are highly regulated in cutaneous SCC. Only desmoglein 2 expression correlates with risk of metastasis. Desmosomes may still be functional in metastasizing tumor cells.

P27 and mib1 expression in actinic keratosis, Bowen disease, and squamous cell carcinoma

The histologic boundary between actinic keratosis, Bowen disease, and invasive squamous cell carcinoma is not clear in many cases. We determined nuclear expression of p27 (a protein associated with cellular quiescence) and Ki-67 (a marker of proliferation) immunohistochemically in actinic keratosis, Bowen disease, and squamous cell carcinoma to see if differential patterns of expression for p27 exist and how these might correlate with Ki-67 expression. We determined a labeling index for p27-stained nuclei and assessed the pattern of Ki-67 expression. The student's t test was used to evaluate the p27 labeling index. The p27 labeling index was decreased in invasive aggregates of squamous cell carcinoma (76.9+/- 1.1%) when compared with those of normal epidermis (97.2+/- 2.4%), actinic keratosis (95.3 +/- 1.4%), and Bowen disease (98.0+/- 0.5%). Ki-67 was expressed in a scattered to confluent linear pattern in the basal/parabasal cell layer of normal epidermis and actinic keratosis. Keratinocytes in squamous cell carcinoma exhibited Ki-67 in the peripheral layers of the neoplasm and frequently within the tumor aggregates. Ki-67 was observed in nuclei throughout the full thickness of the epidermis in Bowen disease. The staining pattern of Ki-67 in Bowen disease separated this entity from others under study. The combination pattern of p27 and Ki-67 staining can be used to support differentiation of actinic keratosis, Bowen disease, and squamous cell carcinoma.

HCR, a candidate gene for psoriasis, is expressed differently in psoriasis and other hyperproliferative skin disorders and is downregulated by interferon-gamma in keratinocytes

We have previously shown that HCR is a good candidate gene for psoriasis based on its location in the PSORS1 locus, predicted secondary structure change of the associated allele, and expression pattern. To understand better the function of HCR, we studied how HCR expression is altered in hyperproliferative skin diseases other than psoriasis and in cancers. We examined also its regulation by different cytokines, growth factors, and antipsoriatic agents using quantitative RT-PCR (TaqMan) analysis and its location by immunostaining of keratinocyte cultures. Compared to psoriasis, HCR protein had a different distribution in chronic dermatitis, pityriasis rubra pilaris, mycosis fungoides, and chronic skin ulcers. In three of six grade III squamous cell carcinomas of the skin, four of four adenocarcinomas of the lung, and two of two ductal breast adenocarcinomas, positive cytoplasmic staining in cancer cells was detected. As in psoriasis, Ki67 did not colocalize with HCR. In cell cultures, HCR staining was detected perinuclearly in the cytoplasm and in the nuclei, suggesting that the protein may have a role in both compartments. A 2-fold downregulation of HCR mRNA expression was observed on stimulation with interferon-gamma. Based on the observations that HCR is detected in cancers of epithelial origin in Ki67-negative areas and that interferon-gamma downregulates its expression, we suggest it to have an antiproliferative function.

Immunolabeling pattern of syndecan-1 expression may distinguish pagetoid Bowen's disease, extramammary Paget's disease, and pagetoid malignant melanomain situ

The differential diagnosis of pagetoid cells within the epidermis rests primarily between pagetoid Bowen's disease (PBD), extramammary Paget's disease (EPD), and pagetoid malignant melanoma (MIS) in situ. Although morphologic clues are often helpful in differentiating these lesions, the use of immunohistochemistry is often necessary to arrive at the correct diagnosis. Syndecan-1 is a cell-surface proteoglycan that mediates adhesion between cells and the extracellular matrix, and between cells themselves. Twenty-two cases of PBD, four cases of intraepidermal EPD, and 13 cases of MIS were examined for syndecan-1 immunoreactivity. Cell-membrane syndecan-1 immunoreactivity was evident in PBD, cytoplasmic syndecan-1 immunoreactivity was evident in EPD, whereas immunoreactivity for syndecan-1 was not present in MIS. The patterns of syndecan-1 immunoreactivity in these lesions may be a useful adjunct in the differentiation of PBD, EPD, and MIS.

High prevalence of epidermodysplasia verruciformis-associated human papillomavirus DNA in actinic keratoses of the immunocompetent population

Skin cancers in both immunosuppressed and immunocompetent populations are associated with epidermodysplasia verruciformis human papillomavirus (EV-HPV) DNA. However, little is known about the prevalence of EV-HPVs in actinic keratoses in immunocompetent individuals. Actinic keratoses from 114 patients were classified as low-grade ( n=76) or high-grade ( n=38) according to the extent of histological atypia. HPV DNA was amplified from 54 frozen and 60 paraffin-embedded biopsy specimens by nested polymerase chain reaction (PCR) with several consensus and type-specific primers. PCR products were sequenced for typing. These results were compared with HPV detection in skin cancers ( n=20) and Bowen's disease ( n=18). A broad spectrum of EV-HPV types including oncogenic HPV5 and HPV8 and partially characterized sequences were detected in actinic keratoses and cutaneous cancers. In actinic keratoses a higher prevalence of EV-HPV DNA was found in frozen tissues than in formalin-fixed tissues (85% vs 67%). There was no difference between the low- and high-grade actinic keratoses either in terms of EV-HPV DNA prevalence or the results of serological study using HPV8 virus-like particles. The detection rate of EV-HPVs was lower in skin cancers and Bowen's disease. This would suggest involvement of EV-HPVs in the early stages of cutaneous oncogenesis.

p16INK4a expression in actinic keratosis and Bowen's disease

BACKGROUND

Progression of cutaneous squamous neoplasms from actinic keratosis (AK) to Bowen's disease (BD; squamous cell carcinoma in situ) has important implications for clinical management and treatment, thus requiring accurate diagnosis. p16INK4a is a cell cycle regulatory tumour suppressor protein that negatively regulates D-type cyclins in the G1 cell cycle phase via intimate interplay with the retinoblastoma gene. Expression of a paraffin-reactive p16INK4a marker has recently been shown to increase in cervical squamous neoplasms as lesions progress from low-grade dysplasia to squamous cell carcinoma in situ. p16INK4a expression in the progression of squamous cutaneous neoplasia, however, has not been evaluated.

OBJECTIVES

To evaluate p16INK4a expression in the progression of squamous cutaneous neoplasia.

METHODS

Biopsies of 203 squamous cutaneous neoplasms with unequivocal features of AK (n = 87) and BD (n = 116) as well as a benign squamous control group (verruca vulgaris: n = 10; seborrhoeic keratosis: n = 11; scar tissue: n = 8) obtained between January and December 2001 at Henry Ford Hospital (Detroit, MI, U.S.A.) were immunostained for p16INK4a (Dako; clone E6H4; dilution 1 : 50) using large core (1.5 mm) tissue microarray analysis. Nuclear/cytoplasmic immunoreactivity in > 10% of neoplastic cells was considered positive.

RESULTS

Of 203 cases, 166 (81.8%) were interpretable (AK 59; BD 107). Mean patient age was 71.0 years (range 33-93); 57% were male. Sites of involvement were: head and extremities 75.9%, trunk/buttocks 21.7%, genital region 2.4%. p16INK4a immunostaining was positive in 90 of 107 (84.1%) BD cases, four of 59 (6.8%) AK cases and none of 29 benign squamous controls. The sensitivity and specificity of p16INK4a for a diagnosis of BD (vs. benign squamous controls/AK) was 84.1% and 95.5%, respectively (P < 0.0001, Fisher's exact test, two-sided).

CONCLUSIONS

p16INK4a is a sensitive and specific marker for distinguishing BD from AK/benign squamous cutaneous lesions and may be helpful as an adjunct to histomorphology in the diagnosis and appropriate clinical management of these lesions.

Human papillomavirus infection in actinic keratosis and bowen’s disease: comparative study with expression of cell-cycle regulatory proteins p21waf1/cip1, p53, pcna, ki-67, and bcl-2 in positive and negative lesions

We examined the presence of human papillomavirus (HPV) DNA in tissues of premalignant skin lesions, i.e., actinic keratosis (n = 13) and Bowen's disease (n = 62), taken from 69 Japanese immunocompetent and renal transplant recipient patients. Detection and typing of HPV DNA were performed using polymerase chain reaction (PCR) and sequence analysis or restriction fragment length polymorphism (RFLP) analysis, respectively. The positivity rates of HPV DNA in tissues of actinic keratosis and Bowen's disease were 77% and 65%, respectively. Twenty-seven HPV types were detected in 50 (67%) premalignant skin lesions, in which Z95963 (accession no. in the EMBL Databank), Z95968, AJ010823, and AJ000151 have been described as partial sequences of unknown HPV types. Furthermore, 2 unknown types, HPVX1 and HPVX2, were found in specimens of actinic keratosis. Sequence analysis showed that HPVX1 is related to HPV-37 (86.1% sequence homology) and that HPVX2 is related to HPV-38 (79.7%). These results indicate that various mucosal and epidermodysplasia verruciformis-related HPV types are associated with the pathogenesis of actinic keratosis and Bowen's disease. In addition, 24 specimens of HPV-positive or HPV-negative premalignant skin lesions were examined immunohistochemically for proliferating cells to determine biological differences between HPV-positive and HPV-negative lesions. Immunohistochemistry for p21(Waf1/Cip1), p53, proliferating cell nuclear antigen (PCNA), Ki-67, and Bcl-2 revealed that there was no significant difference in the cell proliferation activity between HPV-positive and HPV-negative lesions, suggesting that HPV infection alone does not induce cell proliferation in those lesions.

Selective expression of HLA-G in malignant and premalignant skin specimens in kidney transplant recipients

The HLA-G molecule has been implicated in the escape from the host antitumor immune response. Besides, this molecule appears also to be detected in transplant recipient's tissues, mainly those with fewer rejection episodes. Since skin carcinomas develop frequently in organ transplant recipients, we asked whether HLA-G could be expressed in these lesions, therefore allowing tumor development in such patients. Immunohistochemical analysis of kidney transplant recipients presenting various types of epithelial malignant tumor and benign cutaneous lesion was done using a specific anti-HLA-G antibody. HLA-G was expressed in 35% of specimens of SCC, 47% of in situ carcinoma, 27% of AK and 14% of BCC but never in the 24 benign lesions studied. Many benign specimens were obtained from the same patients who had tumors, demonstrating that HLA-G expression was restricted to the malignant sites. Interestingly, HLA-G was expressed by proliferative keratinocytes, inflammatory infiltrates and even endothelial cells. Cytokines triggered in the course of organ transplantation include IL-10. This molecule may induce expression of HLA-G, which in turn may be implicated in tumor development in transplanted recipients.

Pagetoid squamous cell carcinoma in situ (pagetoid Bowen's disease) of the external genitalia

Approximately 5% of cutaneous squamous cell carcinomas in situ (SCCIS) have a nested pattern, referred to as pagetoid SCCIS, or pagetoid Bowen's disease. This growth pattern may simulate extramammary Paget's disease (EPD) when the external genitalia are involved. We report two cases of genital pagetoid SCCIS, including the first example affecting the vulva. Using several known cases each of classic (bowenoid) SCCIS of the vulva, primary cutaneous vulvar EPD, and cutaneous melanoma in situ as controls, we performed a battery of immunohistochemical and mucin stains to study the phenotype of pagetoid SCCIS. Both cases of pagetoid SCCIS were strongly positive for cytokeratin (CK) 7, a highly sensitive and popular marker for EPD. Stains with the high molecular weight cytokeratin marker Keratin-903 (34betaE12) showed 4+ immunoreactivity, although not with the intensity seen in the juxtaposed normal keratinocytes or in the cells of classic SCCIS. Immunoreactivity scores were 2+ for CK5/6, 2+ for CK19, and 1+ to 3+ for CK 13. Unlike the Paget's cells of EPD, the nested cells of pagetoid SCCIS were devoid of mucin and were nonimmunoreactive with GCDFP-15, CEA, CAM5.2, and c-erbB2. Stains for CK20, S-100, and Melan A also were negative. Although CK7 is a sensitive marker for the Paget's cells of EPD, this study corroborates the unexpected CK7 positivity in pagetoid SCCIS, precluding its usefulness in distinguishing these two diseases. Combined with mucin stains, a limited immunohistochemical panel may be of diagnostic value in particularly difficult cases.

The expression of nectin-1alpha in normal human skin and various skin tumours

BACKGROUND

A novel cell-cell adhesion system that consists of nectin and afadin has been identified at cadherin-based cell-cell adherens junctions. Nectin is a Ca2+-independent homophilic and heterophilic cell adhesion molecule that belongs to the immunoglobulin superfamily. Nectin has recently been shown to serve as an alpha-herpesvirus entry and cell-cell spread mediator. In spite of the ubiquitous expression of nectin-1alpha, its detailed localization in human skin has not been examined so far.

OBJECTIVES

To investigate the localization of nectin-1alpha in normal human skin and the alteration of its expression in malignant skin tumours.

METHODS

Immunohistochemistry was employed to determine the expression of nectin-1alpha and other adhesion molecules.

RESULTS

We detected nectin-1alpha in normal human epidermis, follicles and eccrine ducts. Nectin-1alpha was colocalized with E-cadherin at cell-cell adherens junctions of the epidermis. The concentration of the nectin-afadin system at cell-cell adherens junctions was reduced in the early stage of malignant transformation of keratinocytes, such as in basal cell carcinomas and squamous cell carcinomas, where the cadherin-catenin system was preserved. Nectin-1alpha at cell-cell adherens junctions was reduced in human epithelial cancer cells located at the advancing border of the tumour.

CONCLUSIONS

Our results showed that nectin-1alpha is located at cell-cell adherens junctions in human skin and that reduction of nectin-1alpha at cell-cell adherens junctions may be involved in the invasion of squamous cell tumours.

Expression of CD40 and Fas ligand in Bowen's disease, squamous cell carcinoma and basal cell carcinoma

Impaired regulation of apoptosis is known to be associated with the development of various cancers, and Fas/Fas-ligand (FasL) is known to play an important role in apoptosis. CD40 is a cell surface receptor, which when ligated modulates apoptosis in some cell types. The expressions of CD40 and FasL were examined in 10 normal skins, 7 Bowen's disease skins, 10 squamous cell carcinomas (SCCs) and 12 basal cell carcinomas (BCCs) immunohistochemically. In the normal epidermis, CD40 was more highly expressed in the keratinocytes of the squamous cell and granular layers than in those of the basal layer, and FasL expression was observed in the cell membrane of keratinocytes at the basal and squamous cell layers. CD40 expression was significantly higher in SCCs than in normal or Bowen's disease skin, while FasL expression was significantly higher in Bowen's disease than in SCCs. BCCs expressed the lowest levels of CD40 and FasL. These results suggest that altered CD40 and FasL expression may be related with the progression of SCC, and the marked reduced expression of CD40 and FasL may explain the biologic behavior of BCCs.

Comparative histochemical study of Bowen's disease and actinic keratosis: preserved normal basal cells in Bowen's disease

The degree of DNA-instability as revealed by immunohistochemical staining with anti-cytidine antibody after acid hydrolysis (DNA-instability test) has been recently used as a marker of malignancy. This technique was applied to examine 17 skin tissue samples of Bowen's disease, 47 of actinic keratosis, 15 of squamous cell carcinoma, 5 of seborrheic keratosis, and 10 of normal skin. All benign neoplastic cells of seborrheic keratosis and normal epidermal cells were negative. On the other hand, all cancer cells were positive with the DNA-instability test, indicating their malignancy, but all basal cells in Bowen's disease were completely negative. Compatible with this result, the basal cells in Bowen's disease were characteristically normal as evident in other histochemical examinations. Thus, they were negative with p53 immunohistochemistry, with normal signals of chromosome 17 in situ hybridisation and argyrophilic nucleolar organiser region, and showed slightly enhanced proliferative activity as revealed by proliferating cell nuclear antigen immunohistochemistry. Immunohistochemical staining with 34 beta E12 (monoclonal antibody against cytokeratins 1, 5, 10, and 14), which stains all normal epidermal keratinocytes including basal cells, showed that only the basal cells of Bowen's disease stained strongly and homogeneously, while all cancer cells in the upper layers of Bowen's disease and all layers of actinic keratosis were only sporadically or weakly stained. Staining with 34 beta B4 (monoclonal antibody against cytokeratin 1), which recognises the whole epidermis except for the basal layer in the normal epidermis, showed that the basal cells in the Bowen's disease were completely negative, and lower layer cells in the actinic keratosis and upper layer cells in Bowen's disease were only sporadically stained positive, although the superficial layer cells in actinic keratosis stained strongly and homogeneously. Our findings clearly indicate that the basal cells in Bowen's disease are normal. In support of this conclusion, the same cells showed normal morphology on electron microscopy with preserved basement membrane, although the latter was often damaged in actinic keratosis.

Reduced human mismatch repair protein expression in the development of precancerous skin lesions to squamous cell carcinoma

Loss of human mismatch repair (hMSH2) gene function has been linked to hereditary non-polyposis colorectal cancer (HNPCC), Muir-Torre syndrome (MTS), and sporadic cancers, excluding skin cancers unrelated to MTS. We immunohistochemically examined 125 squamous cell carcinomas (SCCs) using a monoclonal antibody to the hMSH2 protein and compared the results with those for 106 precursor lesions of SCC, consisting of actinic keratosis (AK), Bowenoid type of actinic keratosis (BAK), and Bowen's disease (BOD). In contrast to the homogeneous immunoreactivity of proliferating cells composed of AK, BAK, and BOD, heterogeneous and diminished immunostaining to hMSH2 was observed in tumor cells of SCCs examined. In addition, two SCCs (2 of 125; 1.6%) at multiple loci exhibited a complete lack of immunoreaction to hMSH2. Immunohistochemical staining of hMSH2 was semiquantitatively scored as 0 (0% of total cells examined), 1 (less than 10%), 2 (10-50%), or 3 (more than 50%). Percentage preservation of and average score for hMSH2 expression in normal, AK, BAK, BOD, and SCC were 56% and 2.06, 100% and 2.80, 94% and 2.88, 83% and 2.78, 63% and 2.36, respectively. The percentage preservation of and average scores for hMSH2 in AK, BAK, and BOD were significantly higher than those in presumably normal skin (P<0.01). There were no significant differences in the percentage preservation of and average scores for hMSH2 between presumably normal skin and SCC. The score for hMSH2 expression was significantly correlated with score for sun exposure in presumably normal skin of each lesion (R=0.70). These findings for hMSH2 expression in precursor lesions and SCC suggest that promotion or activation of hMSH2 expression may be induced by the increased DNA damage caused by sun exposure and that diminished expression of it might occur according to the transformation from precancerous lesions to SCC.

Patterns of basal cell keratin 14 expression in Bowen's disease: a possible marker for tumour progression

BACKGROUND

Bowen's disease is a well-established in situ malignancy of the epidermis. The keratin expression in Bowen's disease has been studied in many reports. However, the patterns of keratin (K) 14 expression in each case have not been closely examined.

OBJECTIVES

To investigate if the pattern of expression of K14 has a relationship with tumour progression, we analysed the expression patterns of K14 in relation to the nature of tumour cells, comparing tumour cells in direct contact with the dermis, tumour cells separated from the dermis, and tumour cells invading into the dermis.

METHODS

Twenty-seven tissue sections from 22 patients were stained with anti-K14 antibody, as well as with antilaminin and periodic acid-Schiff (PAS) staining to evaluate the conditions of the basement membrane. Staining patterns of K10 and integrin beta1, and their relationships with proliferating cell nuclear antigen (PCNA) and Ki-67 staining patterns, were also examined.

RESULTS

Tumour cells with no, or with obscured, basement membranes always showed positive staining for K14, while those with continuous (intact) basement membranes usually did not. Of 10 sections showing dermal involvement of Bowen's disease, five were K14 positive and five were K14 negative. All of these K14-positive sections with dermal involvement showed negative or obscured laminin and PAS staining. Most of the sections having K14-negative tumour cells with dermal involvement showed K14-positive lining cells with continuous staining with laminin and PAS-positive basement membranes. K10 was reciprocally expressed with K14 in most of the sections. Integrin beta1 was expressed in the basal layers of non-tumour epidermal cells, but not in tumour cells. Ki-67 and PCNA were expressed at high frequencies in tumour cells, clearly demarcating tumour cells from non-tumour cells.

CONCLUSIONS

Tumour cells separated from the dermis by lining cells were K14 negative with PAS- and laminin-positive basement membranes around them; tumour cells without lining cells were K14 positive with or without continuous basement membranes. K14 expression may be a marker of tumour progression in Bowen's disease.

Analysis of p53, p21(Waf1/Cip1) and TGF-beta(3) immunohistochemical staining in Bowen's disease

BACKGROUND

The p53 gene is one of a family of tumor suppressor genes that have been implicated in the genesis of a wide variety of malignant neoplasms including Bowen's disease. Its role in oncogenesis and tumor progression is thought to be of importance. Transforming growth factor beta (TGF-beta) is the most potent known inhibitor of the progression of normal epithelial cells through the cell cycle. p21(Waf1/Cip1) is thought to mediate p53 signaling induced by DNA-damaging agents to arrest the cell cycle.

OBJECTIVE

The present study evaluates the expression of p53, p21(Waf1/Cip1) and TGF-beta(3) protein and speculates on their role in Bowen's disease.

METHODS

Sixteen patients seen at our clinic between 1993 and 2000 were examined. We analyzed p21(Waf1/Cip1), p53 and TGF-beta(3) immunohistochemical staining in all specimens.

RESULTS

In 7 of the Bowen's disease patients, overexpression of p53-positive cells was present in the middle and basal layers, and intense staining of p21(Waf1/Cip1) was observed in the upper spinous layers. In the other 9 Bowen's disease patients, we found positively stained cells for p21(Waf1/Cip1) but negative p53 immunostaining in the upper epidermal layer. Downregulated TGF-beta(3) expression was detected in all layers except the upper spinous layers.

CONCLUSION

These observations suggest different roles for p21(Waf1/Cip1) and p53 within abnormal cells in Bowen's disease. p21(Waf1/Cip1) may induce terminal differentiation to the superficial layer in Bowen's disease via either a p53-independent or -dependent pathway. Moreover, downregualtion of TGF-beta(3) immunostaining provides relevant information concerning the pathogenesis of Bowen's disease.

Expression of granulocyte colony-stimulating factor and its receptor in epithelial skin tumors

Granulocyte colony-stimulating factor receptors (G-CSFR) have been observed on the surface of not only hematopoietic cells but also several cancer cells. In the present study, we investigated the expression of G-CSFR or G-CSF in epithelial skin tumors by immunohistochemical staining. The assessments were defined by the percentage of G-CSFR or G-CSF positive cells and expressed as G-CSFR and G-CSF scores. The G-CSFR score in SCC (77.6+/-20.0%) was significantly higher than that in Bowen's disease (BD) (51.0+/-35.6%), actinic keratosis (AK) (49.3+/-34.6%) or normal skin (30.0+/-32.1%) (P=0.0004, P=0.0003, P<0.0001, respectively). The mean G-CSF score in SCC (56.7+/-27.4%) or in BD (44.1+/-31.4%) was higher than that in normal skin (24.9+/-25.8%) (P=0.0075, P<0.001, respectively). G-CSF expression in AK (29.8+/-31.2%) was lower than that in SCC (P=0.0037). There was significant positive correlation between the G-CSFR score and the G-CSF score (gamma=0.274, P=0.0107) in skin tumors. These findings suggested that the assessment of G-CSFR expression might be associated with carcinogenesis of skin tumors.

Overexpression of transforming growth factor-beta3 immunohistochemical staining in extramammary Paget's disease, but downregulated expression in Bowen's disease

BACKGROUND

The role of transforming growth factor-beta (TGF-beta) in carcinogenesis is complex, with some reports indicating a tumor inhibition role and others indicating a tumor promotion role. In particular, TGF-beta3 is thought to play a key role in controlling epithelial homeostasis. Immunopositive p53 has been demonstrated in a variety of human malignant tumors and its role in oncogenesis and tumor progression is thought to be important. Extramammary Paget's disease (EPD) and Bowen's disease are skin cancers of unknown histogenesis.

OBJECTIVE

To clarify the role of TGF-beta3 and p53 in EPD and Bowen's disease and to better understand the origin of these disorders.

METHODS

Specimens were obtained from 12 patients with EPD and 12 patients with Bowen's disease seen at our clinic between 1993 and 2000. TGF-beta3 and p53 immunohistochemical staining was performed.

RESULTS

In three of the 12 EPD patients and five of the 12 Bowen's disease patients, positive p53 staining was detected. In contrast, TGF-beta3 overexpression was detected in all EPD patients, whereas downregulated TGF-beta3 expression was detected in all Bowen's disease patients.

CONCLUSIONS

The present data suggest different roles for TGF-beta3 in abnormal epidermal cells in EPD and Bowen's disease. Thus, TGF-beta3 expression may be modulated differently via a p53-dependent or -independent pathway in the pathogenesis of EPD and Bowen's disease. Moreover, high TGF-beta expression appears to be a useful indicator of tumor activity in EPD.

Expression of CD40 and CD40 ligand in Bowen's disease and squamous cell carcinoma

CD40 is a member of the tumor necrosis factor receptor super-family expressed by B cells, monocytes, dendritic cells, epithelial cells and hematopoietic progenitor cells. CD40 has recently been reported to be expressed on several epidermal tumors as well. CD40 on epidermal tumor cells interacts with lymphocytes expressing ligand for CD40 (CD40L) or monoclonal antibodies against CD40 with a significant decrease in proliferation. In this study, we examined the expression of CD40 and CD40L in Bowen's disease and squamous cell carcinoma (SCC). CD40 immunoreactivity was observed in a significantly lower proportion of tumor cells from SCC than from Bowen's disease. CD40L mRNA expression was detected in Bowen's disease and SCC by reverse transcriptase polymerase chain reaction (RT-PCR). CD40-CD40L interactions in epidermal tumors may play a role in the proliferation, and the lack of CD40 in tumor cells from SCC might be involved in the mechanisms of escape from the growth inhibitory effect.

E-cadherin expression in skin tumors using an AMeX immunohistostaining method

The AMeX (acetone-methylbenzoate-xylene) method results in good preservation of tissue and morphological details, almost equivalent to that of routinely processed formalin-fixed and paraffin-embedded tissue specimens, and of antigenicity equivalent to that of fresh frozen tissue specimens. It has been reported that the expression of the cell-cell adhesion molecule E-cadherin is often decreased in some types of carcinomas. A decrease in E-cadherin expression is associated with the invasive or metastatic potential of tumor cells. We immunohistochemically examined the expression of E-cadherin with anti-E-cadherin monoclonal antibody in various skin tumors (25 basal cell carcinomas, 11 squamous cell carcinomas, 9 keratoacanthomas, and 11 Bowen's disease) using the AMeX method and found that this method preserved antigenicity well without pretreatment. E-cadherin expression was decreased in 18.2% of squamous cell carcinomas and 33.3% of keratoacanthomas. On the other hand, it was preserved in almost all Bowen's disease and basal cell carcinomas. From the results of our study, we suggest that Bowen's disease and basal cell carcinoma do not have much metastatic potential due to retention of high levels of E-cadherin expression. We hope to apply the AMeX method to other immunohistochemical examinations because this is a very useful staining method.