p53 protein expression in basal cell carcinomas

Comparison of PTCH1, COX-2, p53, and Ki-67 protein expression in basal cell carcinomas of nodular and superficial subtypes arising on the head and trunk

BACKGROUND

There is some evidence that basal cell carcinomas (BCCs) arising on different anatomic sites and developing to different histological subtypes differ in their pathophysiology. The expression of a number of proteins, including PTCH1, COX-2, p53, and Ki-67, is frequently altered in BCC development.

OBJECTIVES

This study sought to determine whether protein expression differs between BCCs at different anatomic sites and of different histological subtypes.

METHODS

Expression of PTCH1, COX-2, p53, and Ki-67 proteins was compared between: (i) BCCs arising on the head (n = 55) and trunk (n = 53), and (ii) nodular (n = 52) and superficial (n = 43) BCCs. The intensity of immunohistochemistry (IHC) staining (low, moderate, strong, very strong) for PTCH1 and COX-2 proteins was measured and the proportions of p53- and Ki-67-positive cells quantified.

RESULTS

The proportion of cells expressing Ki-67 was higher in tumor tissue than in non-malignant epidermis, whereas the opposite was found for PTCH1. The IHC staining intensity for PTCH1 was substantially greater in truncal BCCs than in BCCs on the head (odds ratio [OR] 3.82, 95% confidence interval [CI] 1.63-8.96). The intensity of staining for PTCH1 was greater for superficial than for nodular BCCs (OR 3.70, 95% CI 1.53-8.97), and superficial BCCs showed a higher proportion of Ki-67-positive cells (OR 5.57, 95% CI 1.66-18.67).

CONCLUSIONS

These differences suggest that the pathophysiology of BCC differs between lesions on the head and trunk and between nodular and superficial subtypes, perhaps indicating differences in their etiology.

Genetic algorithm spectral feature selection coupled with quadratic discriminant analysis for ATR-FTIR spectrometric diagnosis of basal cell carcinoma via blood sample analysis

A diagnostic approach for basal cell carcinoma (BCC) has been developed based on investigation of the infrared spectra of blood samples.

B-Raf mutations, microsatellite instability and p53 protein expression in sporadic basal cell carcinomas

Basal Cell Carcinoma (BCC) is the most common skin malignancy. Genes related to the Ras/Raf signalling pathway have been implicated in the pathogenesis of skin cancer. The objective of this study was to investigate the presence of B-Raf mutations in sporadic BCCs as well as its correlation with the phenotype of microsatellite instability (MSI), the clinicopathological parameters of the tumours and p53 protein expression. 83 BCC specimens were screened for B-Raf mutations, applying polymerase chain reaction, single-stranded conformation polymorphism (PCR-SSCP) and DNA sequencing. MSI status was examined using mononucleotide microsatellite markers and p53 protein expression was demonstrated by immunohistochemical staining. A C to T transition at 1790 nucleotide leading to a silent mutation L597L; and a T to A transversion causing an amino acid change (F610I) have been found. MSI was detected in 5% of the cases and p53 accumulation was present in 37/83 samples studied. Although rare B-Raf alterations have been observed in BCC, none of them harboured the hot-spot mutation T1799A commonly present in melanomas and colon carcinomas. Consequently, no correlation could be determined between B-Raf alterations, MSI status, the clinicopathological features and p53 protein expression. Our results are in favour of a secondary importance for Ras signalling cascade genes in BCC pathogenesis.

Expressions of p53, cyclinD1 and histopathological features in basal cell carcinomas

BACKGROUND

We planned this study to analyze probable associations between p53, cyclinD1, Ki67 and histopathological features in basal cell carcinomas (BCC).

METHODS

Histological differentiation types, histological growth patterns and tissue responses were analyzed in 50 cases of BCC. In immunohistochemical analysis, p53, cyclinD1 and Ki67 antibodies were investigated. P53 expression was evaluated based on a cut-off value of 25% positivity. CyclinD1 expression was graded from 0 to 3+ according to the percentage of positive nuclear staining. The percentage of positively staining cells for Ki67 was recorded.

RESULTS

The following significant correlations were detected. Solid infiltrative type differentiation was related to the infiltrative histological growth pattern. The rates of p53 positivity and severe fibrosis in the groups of mixed and infiltrative growth patterns were higher than others. Besides, p53-positive cases showed more severe fibrosis and had a higher mean value for Ki67 index. Epidermal p53 and cyclinD1 clones in normal epidermal areas adjacent to tumors were noticed in 42% and 52% of the cases, respectively.

CONCLUSIONS

P53 expression seems to be related to Ki67 index and some histopathological features of BCC, such as infiltrative histological growth pattern and probably fibrosis.

Diagnosis of basal cell carcinoma by infrared spectroscopy of whole blood samples applying soft independent modeling class analogy

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was applied to discriminate the blood samples obtained from healthy people and those with basal cell carcinoma, demonstrating high accuracy while soft independent modeling class analogy (SIMCA) chemometric technique is benefited. It was aimed to classify the normal case and cancer case blood samples through the use of ATR-FTIR spectroscopy as a rapid method while the sample preparation is so easy in comparison with the common pathologic methods. A total of 72 blood samples, including 32 cancer and 40 normal cases, were analyzed in 1,800-900 cm(-1) spectral region. Results showed 97.6% of accuracy being compared with the current clinical methods. Research results were exemplified with comparable data of other classification methods such as principal component analysis (PCA) and Cluster analysis. The residual errors in prediction (REP) of calibration model for normal and cancerous groups in SIMCA method were 0.00362 and 0.00343, respectively.

Molecular and cellular biology of basal cell carcinoma

The finding of mutations in the PTCH gene in both Gorlin's syndrome and sporadic basal cell carcinomas has significantly advanced our understanding of the molecular defects that lead to the formation of these tumours. Knowledge of the specific molecular and functional changes that have taken place in these tumours will help us devise more defined therapies, as well as give us a better understanding of normal molecular pathways involved in skin development and function. The following is a summary of our current understanding of the molecular and cellular biology of basal cell carcinoma.

p53 expression related to the aggressive infiltrative histopathological feature of basal cell carcinoma

AIMS

To determine whether the p53 protein expression which is involved in the genesis and progression of various malignant tumours may relate to age, sites or the aggressive histopathological feature of the basal cell carcinoma. METHODS ADN RESULTS: One hundred and fifty-eight basal cell carcinoma specimens from Songklanakarind Hospital, southern Thailand, collected from January 1992 to December 2000, were examined by immunohistochemistry using polyclonal anti-p53-CM1 (Novocastra Laboratories, Newcastle, UK; dilution 1:700). p53 protein expression was demonstrated in 48.7% of cases. The multivariate analysis showed that the aggressive infiltrative histopathological type was significantly associated with p53 expression (odds ratio 2.95, 95% confidence interval 1.10-7.90), whereas age, sun-exposure site, cellular response and fibrosis were not.

CONCLUSIONS

The p53 expression is found to be related to the aggressive histopathological feature, which may be of predictive value for the behaviour of basal cell carcinoma. However, this result does not support the relation between sun exposure inducing basal cell carcinoma and p53 protein expression.

p53 expression in skin carcinogenesis and its relationship to cell proliferation and tumour growth

The immunoreactivity of p53 protein was studied in relation to tumour development, histopathological characteristics, cell proliferation, and basement membrane organisation following the induction of skin carcinogenesis in tumour-sensitive and -resistant mouse strains by ultraviolet (UV) irradiation or 7,12-dimethylbenz(a)anthracene (DMBA). In non-neoplastic skin exposed to UV irradiation or DMBA, p53 immunoreactivity was observed in nearly 50% of the basal layer cells. These cells were morphologically and histochemically indistinguishable from the p53-negative cells, occurring similarly in the tumour-producing and the tumour-negative mouse strains and regardless of subsequent tumour formation. In induced epidermal hyperplasia and in benign tumours, p53-positive and proliferating cells constituted 40-50% of all cells in the basal layer, while superficial cells were p53 negative. In dysplastic epidermis, p53-positive cells and proliferating cells were seen in all cell layers. In the case of squamous cell carcinomas, p53-positive proliferating cells in differentiated neoplasms were localised close to the basement membrane and, more frequently, in border areas showing invasion and basement membrane destruction. In horn cysts, centrally located cells were non-proliferating and p53 negative. In moderately differentiated neoplasms, proliferating cells were located closer to the basement membrane, while p53-positive cells were distributed diffusely in the neoplasm. In poorly differentiated neoplasms, p53-positive cells were more common than proliferating cells and were arranged in a diffuse pattern. The results showed that the number and location of p53-positive cells depended upon histology, with a close relationship to tumour type and degree of malignancy, but not on the mode of induction, nor on the animal strain or the relationship to subsequent tumour formation.

Atypical fibroxanthoma versus benign and malignant fibrous histiocytoma. A comparative study of their proliferative activity using MIB-1, DNA flow cytometry, and p53 immunostaining

BACKGROUND

MIB-1 was found to be detectable in formalin fixed, paraffin embedded materials with microwave treatment using Ki-67 monoclonal antibody, and immunostaining has been widely documented as a useful marker of proliferation. Because atypical fibroxanthoma (AFX) is regarded as a fibrohistiocytic tumor with an intermediate potential, the proliferative activity of AFX was compared with that of benign and malignant fibrous histiocytomas.

METHODS

Thirty-eight soft tissue tumors including atypical fibroxanthoma (n = 5), benign fibrous histiocytoma (FH) (n = 17) and malignant fibrous histiocytoma (MFH) (n = 16) were examined using immunohistochemistry to determine MIB-1, DNA flow cytometry, and p53 (PAb 1801) immunostaining.

RESULTS

The mean of the MIB-1 labeling index (MIB-1 LI), defined as the percentage of positive cells for more than 500 cells, was determined in an increasing order as follows: FH, 3.3 +/- 1.8; AFX, 12.2 +/- 6.3; and MFH, 21.5 +/- 10.2. However, the MIB-1 LI of each case in AFX was considerably scattered, and the MIB-1 LI of AFX and MFH overlapped each other. A DNA analysis revealed that the proliferative index (S+G2+M fraction) showed no significant correlation with the MIB-1 LI, and an aneuploid pattern was present in only five (42%) of 12 cases of MFH. p53 positivity was detected in 2 (40%) of 5 cases of AFX and 6 (38%) of 16 cases of MFH.

CONCLUSIONS

Although AFX shows a lower degree in the MIB-1 LI than MFH, the MIB-1 LI shows a limited value in relation to the biologic activity of fibrohistiocytic tumors. Aneuploidy demonstrates a malignant potential in fibrohistiocytic tumors.

The relation between p53 mutation and p53 immunostaining in non-melanoma skin cancer

Extensive study of the p53 gene has established its role as a tumour-suppressor gene, and the involvement of mutant p53 in a wide spectrum of human malignancy. Many mutations of p53 result in a protein product that is abnormally stable, so that it becomes readily detectable by immunocytochemistry. In contrast, under normal conditions, it has been considered that levels of wild-type p53 were too low to be detectable. Although positive immunocytochemistry has been used as a marker of mutation, recent evidence suggests that this assumption may not always be valid. We have carried out both PCR-sequencing of exons 5-8 of the p53 gene in 20 basal cell carcinomas (BCC), and immunocytochemistry of these tumours with the anti-p53 antibody DO7. Twenty cases of Bowen's disease, in which we had previously documented mutations, were also immunostained. We report a low rate of p53 mutation in the BCCs we examined (2/20), and a discrepancy between tumours with positive immunostaining and those with mutation in both Bowen's disease and BCC. Of eight tumours in which we detected mutation, only four were immunopositive: of 19 immunopositive samples, only four showed detectable mutation. We discuss the implications of our results for the use of positive immunostaining in clinical diagnosis, and the involvement of p53 in skin carcinogenesis.