Photodynamic therapy reduces the histological features of actinic damage and the expression of early oncogenic markers.

BACKGROUND: Photodynamic therapy (PDT) has been shown to be effective in treating nonmelanoma skin cancer (NMSC), especially actinic keratosis (AK). Moreover, there is sufficient evidence of its effectiveness in preventing the appearance of premalignant and malignant lesions in organ transplant recipients. OBJECTIVES: To describe the molecular and genetic changes underlying this preventive effect. METHODS: Twenty-two patients with AK were treated with methyl aminolaevulinate and red light. Biopsies were performed before and 6 weeks after the treatment. Conventional histopathology and immunohistochemistry were carried out. RESULTS: Not only was a reduction in the dysplasia and elastosis observed, but also a decreased expression of Ki-67 and p53. The abnormal findings did not disappear completely in all cases. The expression of cyclin D1 remained stable. CONCLUSIONS: These findings show that PDT has the potential to reduce the histological signs of photoageing. Moreover, the reduction of Ki-67, a marker of proliferation and of p53, a marker of early skin carcinogenesis, indicates a reversal of the carcinogenic process. On the other hand, the fact that one treatment does not clear dysplasia and expression of p53 completely, and the persistence of cyclin D1, indicate that one single treatment, despite showing good clinical results, is not sufficient to clear completely the signs of chronic actinic damage, and thus the risk of NMSC.

Expression of p53 and p16 in actinic keratosis, bowenoid actinic keratosis and Bowen's disease.

INTRODUCTION: Bowen's disease (BD) and bowenoid actinic keratosis (bAK) have traditionally been differentiated according to the presence or absence of dysplasia in the follicular epithelium. p16 has been suggested to be a useful tool to make the differential diagnosis between BD and AK and as a marker of bad prognosis. MATERIALS: Five biopsies of BD, five of AK and five of bAK where stained for p53 and p16. RESULTS: All lesions showed positive immunostaining of p53, affecting to the lower two thirds of the epidermis in BD and bAK, and only the basal layer in non-bAK. All the BD and bAK cases were positive for p16, showing a similar immunostaining pattern, whereas no staining was observed in non-bAK. DISCUSSION AND CONCLUSION: These findings suggest a common pathogenic mechanism for BD and bAK. bAK might have worse prognosis than AK. p16 might not be useful as a tool for differential diagnosis between AK and BD because bAK and BD show an extremely similar immunohistochemical pattern.

[Recent advances in laser therapy and other technologies]. / Recientes avances en láser y otras tecnologías.

Laser technology and other energy sources are rapidly finding a place in dermatology clinics. In the field of skin rejuvenation by fractional photothermolysis, although few controlled studies have been undertaken, several devices have emerged in recent years that appear less effective than laser ablation techniques but that are safer. The aim of this short article is to provide an introduction, though not treat in depth, the different emerging technologies in dermatology. We will focus particularly on lasers and light sources in improving applications such as the treatment of vascular lesions, acne, and encapsulated ink tattoos; light-emitting diodes; developments in the treatment of cellulitis; photodynamic therapy; suction methods; scarring; and finally the recent and doubtlessly future introduction of home devices for use in a range of dermatologic applications (depilation, rejuvenation, treatment of acne, etc).