p53 immunoreactivity in non-melanoma skin cancer from immunosuppressed and immunocompetent individuals: a comparative study of 246 tumours

p53 immunoreactivity was examined in 132 cutaneous non-melanoma tumours from renal transplant recipients and in 114 histologically matched specimens from immunocompetent individuals. Skin lesions examined included 52 viral warts, 50 clysplastic keratoses, 51 intraepidermal carcinomas (IEC), 50 invasive squamous cell carcinomas (SCC) and 43 basal cell carcinomas (BCC). Overall, 51% (51/101) pre-malignant skin lesions and 45% (42/93) non-melanoma skin cancers (NMSC) showed p53 immunoreactivity, with extensive (> 50% cells positive) p53 staining in 27% (27/101) of pre-malignant and 20% (19/93) of malignant lesions. 17% (9/52) viral warts showed p53 immunoreactivity, but this was limited to focal or basal p53 staining. p53 immunoreactivity in all tumours was less in transplant than in non-transplant patients and this reached statistical significance for SCCs (p = 0.03).     

Immunohistochemical prognostic criteria in xeroderma pigmentosum

Xeroderma pigmentosum (XP) is a rare inheritable disease characterized by severe sun sensitivity and early development of skin cancers. We compared the expression of cell proliferation markers and cell cycle checkpoint regulators in squamous cell carcinomas (SCC) and basal cell carcinomas (BCC) from patients with and without XP. Immunostaining for p53, Ki-67, and proliferating cell nuclear antigen (PCNA) was determined in SCCs and BCCs from 18 XP patients and 30 controls. Nine of the 18 XP patients had SCC and BCC, and the other nine had only SCC. In the control group, 15 moderately differentiated SCCs and 15 BCCs were evaluated. Expressions of p53, Ki-67 and PCNA in XP and non-XP patients were assessed statistically by using the Chi-square method. Expression of Ki-67 and PCNA was found to be greater in SCC from XP patients than controls (P = 0.021 and P = 0.033, respectively). Expression of PCNA and p53 by BCCs was greater in XP patients (P < 0.001 and P = 0.027, respectively). There was a significant difference in Ki-67 (P < 0.001) and PCNA (P = 0.001) expression between the lesions of the XP patients who died during the follow up and XP patients who survived. In XP patients, SCCs with more than 10% Ki-67 expression and %50 PCNA expression have a poor prognosis. Our results suggest that increased Ki-67 and PCNA expression may be a predictor for recurrence of nonmelanocytic skin cancer and a poor prognosis.     

p63 expression in normal skin and usual cutaneous carcinomas

BACKGROUND: p63 is a p53 homologue that is mapped to chromosome 3q27. This gene encodes six different isoforms, which have either transactivating or dominant negative effects on p53-reporter genes. It has been described that in contrast to p53, p63 seems not to be associated with tumor predisposition, as neither p63 knockout mouse models nor germline p63 mutations are related to an increased risk of tumorigenesis. It has been demonstrated that p63 is a reliable keratinocyte stem cell marker and that it is involved in the maintenance of the stem cell population. Scant data on p63 expression in normal skin, basal cell carcinomas (BCCs), keratoacanthomas and squamous cell carcinomas (SCCs) have been reported. We herein evaluated p63 expression in 16 BCCs, one keratoacanthoma and 13 SCCs. METHODS: Immunohistochemistry according to the streptavidin-biotin-peroxidase technique, using the antibody 4A4 raised against all p63 isoforms, was performed. p63 expression was evaluated in epidermal cells and skin appendages. Semi-quantitative evaluation (-, +, ++, +++) of p63 expression in BCCs, keratoacanthoma and SCCs was carried out. Only nuclear expression was considered as specific. RESULTS: p63 was expressed in the nuclei of epidermal basal and suprabasal cells, in the cells of the germinative hair matrix and the external root sheath of hair follicles, in the basal cells of the sebaceous gland and in the myoepithelial/basal cells of the sweat glands. All terminally differentiated cells were negative for p63. All BCCs showed ++ to +++ immunoreactivity. At variance, keratoacanthomas and grade I and II SCCs showed variable p63 reactivity in a basal layer-like distribution, whereas undifferentiated cells of grade III SCCs showed ++ to +++ positivity. A grade IV spindle SCC showed + immunoreactivity. The SCCs in situ showed remarkable expression of p63 in all cell layers. Terminally differentiated squamous cells were either negative or showed only focal immunoreactivity in the carcinomas. CONCLUSIONS: p63 is consistently expressed in the basal cells of epidermis and cutaneous appendages, including the basal/myoepithelial cells of sweat glands. Based on our findings, the balance of probabilities favors that p63 might play a role in the pattern of differentiation and in the oncogenesis of usual carcinomas of the skin.     

Apoptosis and cellular proliferation in human epidermal squamous cell neoplasia

We examined cell loss (apoptosis) and proliferation in a histopathological spectrum of epidermal squamous cell neoplasia, including 11 cases of solar keratosis (SK), 18 Bowen's diseases (BD) and 19 invasive squamous cell carcinomas (SCC). Apoptotic and proliferative cells were determined by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) and by the detection of nuclear antigen Ki-67, respectively. Few apoptotic cells were observed in normal epidermis, while TUNEL index (TI; percentage of TUNEL-positive cells) was highest for SCCs, followed by BDs and SKs, in the order given. Although the mean Ki-67 index did not differ between SCCs and BDs. both disease types showed a significantly higher index than the SKs. Of SCCs, both TI and Ki-67 index values were significantly higher in poorly than in well differentiated carcinomas. TI was significantly higher in SCCs without P53 immunohistochemical expression than in SCCs with P53 expression, while TI and Ki-67 indices did not correlate with P53 expression in the SKs and BDs. These results suggest that apoptosis reflects not only cell loss, but also proliferative activity in the epidermal neoplastic lesions.     

Curettage-cryosurgery for non-melanoma skin cancer of the external ear: excellent 5-year results

In this 5-year follow-up study, 60 auricular non-melanoma skin cancers, selected at a skin tumour clinic, were treated by a thorough curettage with different sized curettes followed by cryosurgery in a double freeze-thaw cycle. Tumours of the external auditory canal were excluded. Forty-seven basal cell carcinomas (BCCs), nine squamous cell carcinomas (SCCs), three Bowen's disease and one basisquamous cancer were included. The mean diameter of the malignancies was 18 mm (range 5-70). Morphoeiform BCCs, recurrent BCCs with fibrotic component and most of the SCCs were selected for Mohs' micrographic surgery. Forty-two patients with 47 tumours were followed-up for at least 5 years with only one recurrence. Thirteen patients, followed-up for 2-4 years, died from other causes with no sign of recurrence at their last visit. No major problems after treatment were registered and the cosmetic result was good or acceptable in all patients.     

Differential expression of cell survival and cell cycle regulatory proteins in cutaneous squamoproliferative lesions

Previous models of cutaneous carcinogenesis have primarily focused on the regulation of keratinocyte (KC) proliferation and differentiation. However, it has become clear in many neoplastic systems that altered rates of cell death and/or inabilty to undergo growth arrest can also contribute to the development of cancer. Apoptosis-regulatory proteins include those that block apoptosis such as Bcl-2 and Bcl-x, whilst a related protein Bax promotes apoptosis. Cell cycle regulatory proteins include those associated with growth arrest, i.e. p21^waf1, p53, and those associated with proliferation, i.e. Ki-67. Paraffin embedded samples from ten different lesions of squamous cell carcinoma (SCC), Bowen’s disease (BD), keratoacanthomas (KA), and nine normal adult skin samples were stained by immunohistochemistry to detect expression of Bcl-2, Bcl-x, Bax, Ki-67, p21^waf1, p53 and apoptosis (TUNEL assay). Compared to low levels of Bcl-x and Bcl-2 immunostaining in normal skin, all the squamoproliferative lesions had strong and diffuse KC expression of Bcl-x (>80%) but minimal to absent KC Bcl-2 expression (<15%). Bax immunopositivity was limited to the basal layer in normal skin and BD. In contrast, by examining serial sections both Bcl-x and Bax appeared to be coexpressed by the majority of malignant KCs in KA and SCC (>70%). These immunostaining profiles reveal that squamoproliferative lesions, including invasive transformed KCs, preferentially express Bcl-x over Bcl-2, in addition to upregulating their Bax levels. Even though there were numerous TUNEL positive cells in these squamoproliferative lesions, no other evidence of apoptosis was seen reinforcing the necessity to use caution when relying on TUNEL staining for identification of programmed cell death in skin biopsies. Normal sun-exposed skin had low but detectable p53 and rare p21^waf1 KC expression. Significantly higher numbers of p21^waf1 and p53 immunopositive KCs were noted throughout the lesions in BD and SCC in contrast to KA where p53 and rare p21^waf1 immunopositive KCs were primarily limited to the periphery of the tumor cell islands. In general, p53 KC expression was higher in all squamoproliferative lesions and sun-exposed normal skin compared to p21^waf1 expression. Summary of the expression of cell cycle regulatory proteins for both p21^waf1 and p53 KC expression was: SCC>BD>KA, in marked contrast to Ki-67 KC expression which was: BD>KA>SCC. The relatively few malignant cells in SCC that were actively participating in the cell cycle (i.e. Ki-67 positive) suggests that these neoplasms may arise primarily by increased cell survival and resistance to apoptosis rather than by hyperproliferation. These studies emphasize the importance of examining multiple members of protein families that regulate apoptosis, proliferation, growth arrest, and differentiation. It is the overall balance between these cellular phenomena that determine whether a cell remains viable or undergoes programmed cell death and contributes to the appearance of a neoplasm. The overexpression of Bcl-x may confer a survival advantage to malignant KCs unable to growth arrest to repair damaged DNA (mutant p53) and/or undergo terminal differentiation (increased p21^waf1). Thus, mutation or aberrant expression of such proteins may participate in the multistep process of carcinogenesis that gives rise to these squamoproliferative lesions.     

Inflammation is associated with progression of actinic keratoses to squamous cell carcinomas in humans

BACKGROUND: Squamous cell carcinoma (SCC) is a common skin tumour that may metastasize and lead to death. We have observed that before actinic keratoses (AK) progress to SCCs they may become tender and inflamed. In some of these, histological examination shows that they are, in fact, SCCs. OBJECTIVES: To study the progression of AK to SCCs. METHODS: We studied skin tumours from 50 patients with either asymptomatic AK, inflamed AK or SCCs, using immunocytochemistry. The diagnosis of each tumour was confirmed by histological examination. RESULTS: Studies of differentiation using heat shock protein 27 showed a stepwise loss of differentiation as the tumours progressed from asymptomatic AK, through inflamed AK to SCCs. During the inflamed AK phase, there was a marked increase in T lymphocytes and Langerhans cells: the number of infiltrating cells diminished as progression to SCC occurred. There was an increase in immunoreactive p53 and the apoptosis inhibitor bcl-2 as tumours progressed from AK to SCCs, and a decrease in Fas and Fas ligand. CONCLUSIONS: These studies have shown that progression from benign to malignant tumours may be associated with an inflammatory response, which appears to drive malignant conversion, but subsides rapidly following this conversion.     

bcl-2 protein expression in aggressive and non-aggressive basal cell carcinomas

bcl-2, the well known anti-apoptotic gene, cloned more than a decade ago, promotes cell viability without promoting cell proliferation. With few exceptions, high bcl-2 protein expression is associated with a favourable outcome in epithelial tumours. bcl-2 immunoreactivity in basal cell carcinomas (BCCs) is contradictory, with 67-100% immunopositivity being reported. Although BCCs are traditionally regarded as low-grade, indolent tumours, aggressive BCCs (A-BCCs) are mutilative, locally destructive tumours that often recur. bcl-2 protein expression as a predictor of BCC aggressiveness is poorly documented in the English-language literature. The bcl-2 protein immunoprofile of 50 clinically non-aggressive (NA-BCCs) and 25 clinically A-BCCs was investigated. Of the latter, 17 manifested with one, two or three recurrences. bcl-2 protein expression in each of the recurrences was also evaluated. bcl-2 expression was scored as follows: 0-5% positive cells=negative, 6-25%=1+, 26-50%=2+, 51-75%=3+, >75%=4+. "High" labeling encompassed 3+ or 4+ labeling while "low" labeling referred to 1 + or 2 + labeling. Although bcl-2 positivity was noted in all BCCs, low bcl-2 labeling was a statistically significant feature of A-BCCs (p < 0.01). High bcl-2 labeling of NA-BCCs was a reflection of the bcl-2 labeling of the dominant constituent nodular or superficial subtypes. Micronodular BCCs revealed 2+ or 3+ labeling. Initial and recurrent A-BCCs with a pure or predominantly infiltrative component, demonstrated 1+ or 2+ bcl-2 labeling. The differential bcl-2 expression in the various clinicopathological subtypes of BCCs suggests that, despite the common derivation of these tumours from a primitive basaloid stem cell and a limited potential for metastasis, they form a heterogeneous group of tumours that differ markedly in histologic and biological behaviour. While the superficial and nodular BCCs are indolent slow-growing tumours with high bcl-2 labeling, the aggressive BCCs are infiltrative, desmoplastic tumours with low bcl-2 labeling. In mixed tumours, heterogeneity of labeling is a distinctive feature and is contributed to in part by the labeling trends of the different histological subtypes. The micronodular BCC shows varied bcl-2 labeling but in combined tumours occupies a niche intermediate between the non-aggressive nodular and superficial and the aggressive infiltrative subtypes. The initial and subsequent biopsies of recurrent, adequately excised BCCs share a pure or mixed, predominantly infiltrative, stroma-rich histomorphology with low bcl-2 labeling, reflecting the immunoprofile of a more aggressive growth pattern.     

Somatic mutations in the PTCH, SMOH, SUFUH and TP53 genes in sporadic basal cell carcinomas

BACKGROUND: Basal cell carcinoma (BCC) of the skin is the most common human cancer. The genetic alterations underlying BCC development are only partly understood. OBJECTIVES: To investigate further the molecular genetics of sporadic BCCs, we performed mutation analyses of 10 skin cancer-associated genes in 42 tumours. METHODS: Single-strand conformational polymorphism analysis followed by DNA sequencing was used to screen for mutations in the sonic hedgehog pathway genes PTCH, SMOH, SUFUH and GLI1, in the TP53 tumour suppressor gene, and in the proto-oncogenes NRAS, KRAS, HRAS, BRAF and CTNNB1. Microsatellite markers flanking the PTCH, SUFUH and TP53 loci at 9q22, 10q24 and 17p13, respectively, were studied for loss of heterozygosity (LOH). RESULTS: PTCH mutations were found in 28 of 42 tumours (67%). Microsatellite analysis revealed LOH on 9q22 in 20 of 38 tumours investigated (53%), including 14 tumours with and six tumours without PTCH mutations. SMOH mutations were identified in four of the 42 BCCs (10%) while two tumours demonstrated mutations in SUFUH, including one missense mutation and one silent mutation. None of the BCCs showed LOH at markers flanking the SUFUH locus. Seventeen BCCs (40%) carried TP53 mutations, with only three tumours showing evidence of biallelic TP53 inactivation. TP53 mutations were present in BCCs with and without mutations in PTCH, SMOH or SUFUH. Interestingly, 72% of the TP53 alterations were presumably ultraviolet (UV)-induced transition mutations. In contrast, only 40% of the PTCH and SMOH alterations corresponded to UV signature mutations. No mutations were identified in GLI1, NRAS, KRAS, HRAS, BRAF or CTNNB1. CONCLUSIONS: Our data confirm the importance of PTCH, SMOH and TP53 mutations in the pathogenesis of sporadic BCCs. SUFUH alterations are restricted to individual cases while the other investigated genes do not appear to be important targets for mutations in BCCs.     

皮肤鳞状细胞癌和基底细胞癌中细胞凋亡及c-fos、BNIP1表达

目的观察皮肤鳞状细胞癌(鳞癌)和基底细胞癌(基癌)中细胞凋亡及其与c-fos、BNIP1表达的关系。方法应用原位末端标记和原位杂交技术检测48例皮肤鳞癌和41例基癌标本中细胞凋亡及C-fos、BNIP1 mRNA表达。结果鳞癌中凋亡指数(AI)、c-fos mRNA表达明显高于基癌(P＜0．01),但BNIP1 mRNA表达在二者间的差异无显著性(P＞0．05)。AI在高分化鳞癌中明显增多(P＜0．05),但C-fos表达以低分化鳞癌更为明显(P＜0．05)。鳞癌中AI与c-fos、BNIP1表达呈显著正相关(P＜0．05)。结论鱗癌中细胞凋亡增多与c-fos表达上调相关,BNIP1在鳞癌和基癌中可能起促凋亡作用。     

Differential expression of p53 and Ki-67 proteins in classic and iatrogenic Kaposi's sarcoma

In many neoplasms, the finding p53 immunoreactivity correlates with striking cytologic atypia, a high tumor cell proliferation rate, and poor prognosis. The literature regarding p53 and Ki-67 (a nuclear proliferation-associated antigen) immunoreactivity in Kaposi's sarcoma is limited. We aimed to: (1) evaluate the role of p53 in the development of Kaposi's sarcoma; (2) determine whether there is a correlation between p53 and Ki-67 protein expression; and (3) determine possible differences between classical Kaposi's sarcoma, known usually to have a benign course, and iatrogenic Kaposi's sarcoma, the course of which is unpredictable, by studying the differential expression of p53 and Ki-67. Among 26 cases of classic KS and 19 of iatrogenic KS, 12 were classified histopathologically as early type and 33 as mixed or spindle-cell type. P53 and Ki-67 immunoreactivity correlated significantly with the histopathologic stage of KS (r=0.63, p=0.0001; r=0.42, p=0.0084, respectively). P53 was not detected in any of the cases in an early histopathologic stage but was present in 55% of the cases in a more advanced stage. The spindle cells increased in proportion with the histopathologic progression and were more often positive (p=0.019) and displayed more extensive staining than the endothelial cells (p=0.0001). There was a strong positive correlation between p53 and Ki-67 protein expression (r=0.43, p=0.0087). There was no correlation between the expression of either p53 or Ki-67 and the extent of the eruption. The expression of p53 and Ki-67 was significantly lower in iatrogenic cases than in the classic cases (p=0.009, p=0.0014, respectively), although no statistical difference was found between the histopathologic stages in the two clinical forms of KS. P53 immunoreactivity was detected in 79% of the cases of classic Kaposi's sarcoma in the mixed or spindle cell stage but in only 21.5% of the iatrogenic cases showing the same histopathologic stage (p=0.001), and the percentage of spindle cells as well as the endothelial cells expressing p53 was higher in the classic cases than in the iatrogenic cases (p=0.0032, p=0.0142, respectively). We conclude that p53 immunoexpression is a marker of tumor progression in classic Kaposi's sarcoma but not in most cases of iatrogenic Kaposi's sarcoma. The proliferative activity of the tumor cells in classic Kaposi's sarcoma is much higher than in iatrogenic Kaposi's sarcoma. Our work implies that the molecular steps involved in classic and iatrogenic Kaposi's sarcoma differ.     

Overexpression of p53 protein associated with proliferative activity and histological degree of malignancy in solar keratosis

BACKGROUND: Overexpression of p53 protein has frequently been demonstrated in human epithelial neoplasms including squamous cell carcinoma (SCC) and solar keratosis (SK). SK is a precursor lesion of SCC. In SCC of the skin, we have already reported that overexpression of p53 protein is associated with the proliferative activity, which is indicated by the percentage of Ki-67-positive cells. In SK, however, the significance of p53 overexpression is still unclear. OBJECTIVE: The aim of the present study was to clarify the relationship between p53 overexpression and proliferative activity, and between p53 overexpression and histological degree of malignancy in SK. METHODS: Sixty-eight cases of SK were divided into four grades according to the proportion of atypical cells in the epidermis (in grade I, up to 25% of the epidermal cells are atypical, in grade II 25-50%, in grade III 50-75%, in grade IV more than 75%) and were immunohistochemically analyzed for the expression of p53 protein and Ki-67 antigen. RESULTS: p53 overexpression was detected in 58 out of the 68 cases of SK. The percentage of p53-protein-positive cells (DO-7 index) ranged from 0 to 78.8 (mean +/- SD = 20.6 +/- 21.6). Mean DO-7 indices were 7.9 in grade I, 26.7 in grade II and 38.3 in grade III. The differences in mean DO-7 index between grades I and II and between grades I and III were statistically significant (p < 0.001). The percentage of Ki-67-antigen-positive cells (MIB-1 index) ranged from 0.8 to 38.2 (mean +/- SD = 10.5 +/- 9.0). Mean MIB-1 indices were 5.9 in grade I, 10.7 in grade II and 20.5 in grade III. The differences in the mean MIB-1 index between grades I and II and between grades II and III were statistically significant (p < 0.01). Cases with higher DO-7 indices tended to show higher MIB-1 indices, and the relation was statistically significant [y = 0.272x + 4.8; correlation coefficient r = 0.59 > r (n - 2, 0.01) = 0.31]. CONCLUSION: Overexpression of p53 protein was related to cell proliferation as well as histological degree of malignancy in SK. Dysfunction of p53 protein might be implicated in skin carcinogenesis.     

Hyaluronan,CD44 and versican in epidermal keratinocyte tumours

BACKGROUND: The high molecular weight polysaccharide hyaluronan is a major component of the extracellular matrix between the vital cells of human skin epidermis. The levels of hyaluronan, and those of the hyaluronan receptor CD44 and the hyaluronan binding proteoglycan versican, correlate with the aggressiveness of different human carcinomas of epithelial origin. OBJECTIVES: To study skin keratinocyte tumours for the expression of hyaluronan, the hyaluronan receptor CD44 and the hyaluronan binding proteoglycan versican. METHODS: Paraffin-embedded sections of 114 basal cell carcinomas (BCC), 31 in situ carcinomas (ISC) and 35 squamous cell carcinomas (SCC) were stained with a hyaluronan specific probe, biotinylated hyaluronan binding complex, and with monoclonal antibodies against CD44 and versican. RESULTS: Compared with normal epidermis, ISC and well differentiated SCCs showed an enhanced hyaluronan signal on carcinoma cells while CD44 expression level resembled that of normal skin. Less differentiated SCCs showed reduced and irregular expression of both hyaluronan and CD44 on carcinoma cells. In BCCs, hyaluronan and CD44 signals were absent or very low on the surface of carcinoma cells. However, hyaluronan was frequently present on BCC cell nuclei, a feature completely absent in ISC, SCC and normal epidermis. An accumulation of hyaluronan in the connective tissue stroma around the tumour was more frequent in SCCs than BCCs. Versican staining was positive around hair follicles and dermal blood vessels of normal skin. Peritumoral versican signal was present in a part of the BCCs but not in other tumours. CONCLUSIONS: The completely different hyaluronan and CD44 expression patterns in BCC and SCC probably reflect the different origins of the tumours, with BCC an undifferentiated keratinocyte and SCC a keratinocyte at an early stage in the differentiation pathway. The difference in hyaluronan and CD44 expression between these tumours may also contribute to the difference in their capacity to metastasize.     

Lamin expression in normal human skin,actinic keratosis,squamous cell carcinoma and basal cell carcinoma

BACKGROUND: Aberrant expression patterns of nuclear lamins have been described in various types of cancer depending on the subtype of cancer, its aggressiveness, proliferative capacity and degree of differentiation. In general, the expression of A-type lamins (lamins A and C) has been correlated with a non-proliferating, differentiated state of cells and tissues. OBJECTIVES: To establish and compare the expression patterns of lamins in normal human skin, actinic keratosis (AK), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). METHODS: Expression patterns of the individual lamin subtypes were studied immunohistochemically. The proliferation capacity of the tumour cells was detected using a specific antibody to Ki-67, and was related to the A-type lamin expression patterns. RESULTS: In normal skin, lamin A was expressed in the suprabasal cell compartment of the epidermis, whereas the basal cells were mostly unstained. BCCs and SCCs stained positive in most cells, while the epidermis overlying BCC and SCC and the epidermis in AK stained homogeneously and strongly in the basal cells in addition to the suprabasal cells. Lamin C was expressed in some basal cells of normal epidermis while the suprabasal cells stained strongly positive. Both BCCs and SCCs stained strongly positive for lamin C, with the difference that in BCC the staining was predominantly present in nucleolar structures with occasional staining of the nuclear envelope. The epidermis overlying SCC showed strong positivity in the lamina of virtually all cells. The expression of lamin C in the basal cells of AK resembled the expression pattern seen in the epidermis overlying BCC, i.e. a nucleolar staining next to nuclear envelope staining. Lamin B1 and B2 were found in virtually all cells in normal epidermis, AK, BCC, SCC and the epidermis overlying cancer. The percentage of Ki-67-expressing cells was highest in BCC (45%), and gradually decreased via epidermis overlying BCC, AK, SCC, and epidermis overlying SCC, to normal skin (11%). Simultaneous expression of A-type lamins and Ki-67 occurred in approximately 50% of the proliferating (Ki-67 positive) cells in BCC and SCC. CONCLUSIONS: Significant changes occur in the expression patterns of A-type lamins in both premalignant and malignant lesions of the skin. The profound overlap of lamin A and Ki-67 staining patterns indicates that the proliferating tumour cells may obtain a certain degree of differentiation. Finally, lamin A expression in the basal cell layer of the apparently normal epidermis overlying BCC may suggest its involvement in the primary process.     

Expression of apoptosis regulatory proteins p53 and Bcl-2 in skin of patients with chronic renal failure on maintenance haemodialysis

BACKGROUND: Chronic renal failure results in multi-organ system derangement including cardiovascular, gastrointestinal, neurological, endocrinal, blood and dermatological abnormalities. Maintenance of skin homeostasis requires a delicate balance between proliferation, differentiation and apoptosis. p53 and Bcl-2 proteins play a central role in the regulation of apoptosis. OBJECTIVE: Evaluation of the expression of apoptosis regulatory proteins p53 and Bcl-2 in apparently normal skin of patients, with chronic renal failure on maintenance haemodialysis, with respect to their role in the apoptotic process. METHODS: Biopsy specimens were obtained from 10 patients with chronic renal failure on maintenance haemodialysis, as well as seven age-matched control subjects. Computer-assisted image analysis was employed to measure epidermal thickness in H&E-stained sections. Immunoperoxidase technique was also used to demonstrate p53 and Bcl-2 proteins and the TUNEL technique for detection of apoptotic cells in these specimens. RESULTS: The mean epidermal thickness was significantly higher (P < 0.0001) in patients than controls. Meanwhile, no apoptotic cells were detected in the epidermis of patients. On the other hand, a statistically significant difference was observed in both p53 (P = 0.0001) and Bcl-2 expression (P = 0.0003) when comparing patients and controls. Expression of p53 (2.74 +/- 0.84) and Bcl-2 (3.45 +/- 1.35) proteins was higher in skin samples obtained from patients with chronic renal failure and on maintenance haemodialysis than those from control cases (0.5 +/- 0.96 and 0.8 +/- 0.6, respectively). Moreover, Bcl-2 expression in patients was observed in basal as well as squamous cell layers of skin, whereas in control subjects it was confined to the basal cell layer only. CONCLUSION: These findings suggest that an alteration in the proliferation/apoptosis balance may be present in the skin of such patients.     

Expression of lamins depends on epidermal differentiation and transformation

BACKGROUND: It has been suggested that A- and B-type lamins, proteins of the nuclear lamina, play important roles in the morphogenesis of the nucleus and cellular differentiation. OBJECTIVE: To investigate the expression of these nuclear proteins in normal skin and some keratinocytic tumours of the skin. METHODS: We examined by means of immunohistochemistry the expression of lamins in normal skin and some keratinocytic tumours of the skin, such as squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease, solar keratosis, keratoacanthoma and seborrhoeic keratosis. RESULTS: In normal skin, A-type lamin was expressed in all epidermal cells, but the expression level of B-type lamins diminished from basal cells to granular cells. In keratinocytic tumours, the expression of A-type lamin was reduced, especially in BCCs, Bowen's disease and poorly differentiated SCCs. B-type lamins were reduced and exhibited heterogeneous expression patterns in most well-differentiated SCCs and keratoacanthomas. Antibodies against B-type lamins stained only peripheral cells of the lobules in keratoacanthomas, while no regular staining patterns were seen in well-differentiated SCCs. CONCLUSIONS: Lamin expression depends on the differentiation and transformation of the human skin. This finding should be useful for the diagnosis of keratinocytic tumours.     

Expression of bcl-2, p53 and Ki-67 in arsenical skin cancers

To investigate the regulation of apoptosis and proliferation in arsenic-induced skin cancers, we examined the expression of bcl-2. p53, and Ki-67 using immunohistochemical staining. Thirty patients with Bowen's disease (BD), ten with basal cell carcinoma (BCC), eight with squamous cell carcinoma (SCC) and eleven of perilesional normal skin (PLN) of the non-sun exposure sites from endemic area were examined. The results showed that: 1) bcl-2 was expressed in all of the BCC homogeneously, in none of the SCC, and in 12/30 of the BD focally or homogeneously; 2) p53 was expressed in all of the arsenical skin cancers with a labelling index of 75±14% of BD, 50±17% of BCC. 61±15% of SCC, and also in all of the perilesional normal skin with a labelling index of 55±24%; 3) Ki-67 was expressed in all of the skin cancers with labelling index of 58±17% of BD. 12±7% of BCC, 47±21% of SCC, and in 9/11 of PLN with a labelling index of 41±24%. Expression of bcl-2 in BCC or BD is related to the phenotype of germinative basal cell. The constant expression of bcl-2 i early dysplastic cells of BD and the earliest expression of P53 in the basal cells of perilesional normal skin indicate that the initial step of arsenic-induced carcinogenesis is from the basal germinative cells. There is no mutual relationship between bcl-2, p53 or Ki-67 expression in any type of the arsenical skin cancers, but there is a positive correlation between p53 and Ki-67 expression identified in perilesional normal skin. BD had the highest labelling index of p53 and Ki-67.     

A broad spectrum of human papillomavirus types is present in the skin of Australian patients with non-melanoma skin cancers and solar keratosis

BACKGROUND: Human papillomavirus (HPV) may play a role in the pathogenesis of non-melanoma skin cancer (NMSC) in epidermodysplasia verruciformis (EV) patients, but in the general population no specific HPV types have been associated with these lesions. Objectives To examine the spectrum of HPV types present in the skin and tumours of Australian patients with NMSC or solar keratosis (SK). METHODS: Biopsies from tumours, and cotton swab samples of perilesional skin and buttock skin from each of 59 Australian patients with basal cell carcinoma (BCC), squamous cell carcinoma (SCC) or SK were tested for HPV DNA by polymerase chain reaction (PCR) using HPV consensus (FAP) primers and by type-specific primers for HPV 38 and candidate HPV 92. The identification of HPV type from consensus PCR was performed by sequencing and comparison with GenBank. RESULTS: In total, 49 of 59 (83%) patients harboured HPV DNA, which was detected in 28 of 64 (44%) biopsies, 48 of 64 (75%; P < 0.001) perilesional swabs and 36 of 59 (61%; P = 0.04) buttock swabs. Forty-five different HPV types/putative types were detected: 15 were previously characterized HPV types, 17 were earlier described putative types and 13 were new putative types. In addition, six subtypes and four variants of HPV sequences were identified. HPV types within the B1 group (EV HPV types) were found in 26 of 64 (40%) lesions, 44 of 64 (69%) perilesional swabs and 35 of 59 (59%) buttock swabs. HPV 38 was detected in 23 of 59 (39%) patients, and was found in seven of 16 (43%) SKs, but was less common in SCCs [three of 23 (13%); P = 0.037] and BCCs [four of 25 (16%); P = 0.056]. Candidate HPV 92 was found in seven of 59 (12%) patients. CONCLUSIONS: A broad spectrum of HPV types, the majority from the B1 group, was found in skin of Australian patients with skin tumours. HPV 38 was found significantly more often in SK than in SCC. However, the role of cutaneous HPV infection in the pathogenesis of NMSC remains elusive.