Altered p53 expression in benign and malignant skin lesions from renal transplant recipients and immunocompetent patients with skin cancer: correlation with human papillomaviruses?

Dermatologic findings in renal transplant recipients: Possible effects of immunosuppression regimen and p53 mutations

OBJECTIVE

To analyze the dermatologic lesions and possible effects of immunosuppression treatment and p53 gene mutations on dermatologic findings in renal transplant recipients.

MATERIALS AND METHODS

The study included 163 renal transplant recipients. After dermatologic examination, cultures, and histopathologic and genetic analyses were performed. A single-strand conformation polymorphism technique was used to analyze p53 gene mutations. Patients were categorized into 3 groups according to time since the transplantation procedure. Results were analyzed using the χ(2) test, using a software program (SPSS version 13.0; SPSS, Inc, Chicago, Illinois).

RESULTS

Mean (SD) age of the 163 transplant recipients (65 women and 98 men) was 40 (11) years, and posttransplantation follow-up was 65 (55) months. The most frequently observed drug-related lesion was hypertrichosis, in 46 of 150 patients. Of 115 lesions, the most commonly observed were verruca vulgaris (n = 34) from viruses, and pityriasis versicolor (n = 21) from superficial fungal infections. Of the total group, 20 patients (12.2%) were mutation carriers. Compared with the entire cohort, the group with premalignant lesions demonstrated more p53 mutations (11% vs 50%; P = .004). Patients given cyclosporine therapy exhibited more premalignant or malignant cutaneous lesions compared with patients who received other agents (P = .03).

CONCLUSION

Patients carrying p53 mutations developed a malignant lesion in the late posttransplantation period, which suggests the importance of prediction of risk.

Ultraviolet radiation and immunosuppression

Ultraviolet (UV) radiation is a complete carcinogen. The effects of UV radiation are mediated via direct damage to cellular DNA in the skin and suppression of image surveillance mechanisms. In the context of organ transplantation, addiction of drugs which suppress the immune system add greatly to the carcinogenicity of UV radiation. This review considers the mechanisms of such effects.

Clinical, Histologic, and Immunohistochemical Analyses of Feline Squamous Cell Carcinoma In Situ

Actinic keratosis (AK) and Bowenoid in situ carcinoma (BISC) are two distinct forms of in situ squamous cell carcinoma in felines. They usually occur on different locations and present with specific clinical and histologic features. However, in some cases, these diseases cannot be distinguished either clinically or histopathologically. The aim of the present study was to determine the accuracy of diagnosis based on clinical or histologic criteria alone, and whether immunohistochemistry for papillomavirus or p53 can improve the accuracy of diagnosis. A series of in situ squamous cell carcinoma cases ( n = 45) were selected according to their location and initial histologic classification and subsequently classified as AK ( n = 22) or BISC ( n = 23) according to the clinical criteria and were reevaluated histologically by 2 dermatopathologists. All BISC cases and most of the AK cases ( n = 15) were confirmed histologically. In 7 cases clinically classified as AK, this diagnosis was not unanimously confirmed histologically because of the presence of overlapping features. P53 immunoreactivity was observed in 11/14 (79%) confirmed AK cases and in 4/22 (18%) BISC cases, while papillomavirus antigen was not detected in any confirmed AK case but was detected in 11/23 (48%) BISC cases. It was concluded that BISC can usually be reliably diagnosed histologically. The histologic diagnosis of lesions clinically suggestive of AK might sometimes be difficult. Results of immunohistochemistry for p53 and papillomavirus antigen were supportive for a role of sun exposure and papillomavirus in the pathogenesis of AK and BISC, respectively.

Detection of DNA by scraping the formalin-fixed paraffin-embedded tissue

BACKGROUND

Pakistan is a developing country and most of the research laboratories have limited required infrastructures for the diagnosis of cancer at molecular level. The polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded tissues is becoming a popular procedure in the research centres. The study was conducted to introduce two new methods of DNA extraction for the PCR from formalin-fixed paraffin-embedded sections of surgical pathology specimens.

MATERIALS AND METHODS

Two methods of DNA detection were used. In method A the formalin-fixed tissues were grossed, proper sections were taken, processed in an automatic tissue processor, embedded in paraffin blocks, and microtomic sections were made. In method B, the procedure was the same until embedding in the paraffin blocks, after which the selected paraffin blocks were set on a black card paper (4 cm x 4 cm) and 1 mg of pure scraped tissue was obtained using a scalpel, manually without using microtone.

RESULTS

DNA was successfully extracted but point mutation of p53 gene was not seen in SCP while it was determined in 96 and 93.75 per cent cases of SCC by method A and method B respectively. There was no statistical difference in the results by both methods (P = 0.359).

CONCLUSION

Scraping of the tissue for DNA detection was a simple method and may be performed in any laboratory. The reliability, reproducibility, and quality assurance of the present results are consistent with the already established techniques of DNA extraction for PCR.

Expression of p53 in the evolution of squamous cell carcinoma: Correlation with the histology of the lesion

BACKGROUND

The evolution of squamous cell carcinoma (SCC) on sun-exposed areas is a multistep process triggered by ultraviolet radiation (UVR), in which precursor lesions exist. However, the exact classification of the various lesions in this process, mainly solar keratosis (SK), is still disputed, and its pathogenesis requires further clarification.

OBJECTIVE

To further elucidate the evolution of SCC on sun-damaged skin by correlating the levels of p53 protein expression, a parameter that reflects UVR damage to cells, and the morphology of the lesions that develop on sun-exposed areas.

METHODS

Biopsy specimens from normal skin (n = 4), normal skin with various degrees of solar elastosis (SE) (n = 16), various degrees of SK (n = 17) and SCCs from sun-exposed (n = 12) and sun-protected (n = 7) areas were stained with anti-p53 antibodies. A semiquantitative evaluation of the degree of staining was performed and correlated with the histological features.

RESULTS

Nuclear staining in keratinocytes was observed already in normal skin with mild SE and was increased gradually to its highest level of expression in advanced SK. It was also expressed in SCCs, but to a lesser degree. Statistical analysis revealed association between the morphology of the lesion and the level of p53 expression (P < .01); it also showed that in general the level of p53 is correlated with the histology of the lesion (P < .001). Furthermore, with regard to p53 expression, two groups of lesions exist: one showing a low level of expression of p53 that includes normal skin, skin with various degrees of SE and SCC from sun-protected areas, and a second group showing a high level of expression that includes SK and SCC occurring on sun-damaged skin.

LIMITATION

This is an immunohistochemical study of relatively few cases and in which the antibody detects all types of p53 protein.

CONCLUSIONS

This study furnishes further evidence that the development of SCC on sun-damaged skin is a gradual process not only morphologically but also on the molecular level. The process starts already in normal-appearing epidermis with SE. In that respect, SK should be regarded as a part of the continuum in the development of SCC, analogous to the situation in other epithelia. The molecular events involved in the development of SCC on sun-exposed areas may be different from those involving the development of SCC on sun-protected areas.

Human leukocyte antigen type as a risk factor for nonmelanomatous skin cancer in patients after renal transplantation

Renal-transplant recipients are at an increased risk for developing nonmelanomatous skin cancer (NMSC). Recipient human leukocyte antigen (HLA) type has been suggested as a possible risk factor. We studied the association between HLA type and posttransplant NMSC in 2,433 renal-transplant recipients in a Northern climate, for whom HLA type and clinical follow-up were available. One hundred six (4.3%) patients developed NMSC between 1984 and 1997. Of previously reported HLA-associated risk factors, only HLA A11 showed an increased incidence of posttransplant skin cancer, at 8% (P=0.0137, odds ratio 2.03 with 95% confidence interval 1.11-3.53) in 1998. This effect persisted at follow-up, in a limited reanalysis in 2004. HLA A11 may be a useful marker, in some populations, for identifying at the time of transplantation those patients that are at an increased risk for NMSC and who may therefore be good candidates for preventative clinical trials.

Human Papillomavirus and Overexpression of P16INK4a in Nonmelanoma Skin Cancer

BACKGROUND

P16INK4a overexpression has been identified as a specific biomarker in high-risk human papillomavirus (HPV)-infected cervical (pre)cancer lesions.

OBJECTIVE

To evaluate the overexpression of this cyclin-dependent kinase inhibitor in skin tumors depending on HPV infections, we analyzed normal skin, benign skin disease, and skin cancer specimens.

METHODS

Biopsies of 23 patients with normal histology (3), psoriasis (2), verrucae vulgaris (2), actinic keratoses (5), squamous cell carcinoma (SCC) in situ (3), Bowen's carcinoma (1), and SCC (7) were analyzed. Specimens of 23 patients were immunostained using the monoclonal antibody E6H4 specific for p16INK4a. HPV status was assessed by a polymerase chain reaction (PCR) system to detect all currently known HPV types. MY (MY09/MY11 and MYN9/MYN10)-, CP (CP65/CP70 and CP66/CP69)-nested PCR, and three single PCR methods CN1, CN3, and CN4 were used in a first step, and HPV typing was performed by restriction fragment length polymorphism analysis. Only beta-globin-positive patients were included in this study.

RESULTS

HPV DNA was detected in all actinic keratoses, SCC in situ, Bowen's carcinoma, and SCC, in 50% (one of two) of verrucae vulgaris, in 66% (two of three) of normal skin, and in none of two psoriasis. P16INK4a expression was not detected in normal skin, psoriasis, and verrucae vulgares. Overexpression of p16INK4a was detected in a subset of dysplastic cells (10% to 80%) of all skin (pre)cancer lesions such as actinic keratoses, SCC in situ, Bowen's carcinoma, and SCC infected with HPV independent of sun exposure.

CONCLUSION

P16INK4a appears to be overexpressed in a portion of dysplastic cells from actinic keratoses and SCC. Further studies to examine the association of HPV infection and the overexpression of p16INK4a are warranted.

Human papillomaviruses and non-melanoma skin cancer

Epidemiological and experimental studies have overwhelmingly confirmed human papillomaviruses as important causal agents in anogenital carcinogenesis. A role for human papillomaviruses has also been proposed in a diverse range of other malignancies, and particular interest has focused on non-melanoma skin cancer, the commonest malignancy in fair-skinned populations worldwide. Although the evidence for this is considerably less convincing than for anogenital cancer, important epidemiological and functional data have emerged over the past year that have furthered our understanding of the possible contribution of human papillomaviruses to skin cancer. Epidemiological human papillomavirus DNA detection studies have shown associations with non-melanoma skin cancer, but have also emphasized the ubiquity of epidermodysplasia verruciformis human papillomavirus types in normal skin, hair follicles and benign hyperproliferative disorders, as have seroepidemiological approaches. Functional investigations have demonstrated mechanistically relevant interactions between the virus and ultraviolet radiation, host cytokines and cellular proteins including p53 and the pro-apoptotic protein Bak. Taken together, these data have advanced our understanding of the contribution of human papillomaviruses to malignant transformation in cutaneous keratinocytes, but further research is required before a causal association between human papillomaviruses and skin cancer is reliably confirmed.