Epithelial-to-mesenchymal transition contributes to invasion in squamous cell carcinomas originated from actinic keratosis through the differentiated pathway, whereas proliferation plays a more significant role in the classical pathway.

BACKGROUND: Every actinic keratosis (AK) starts with atypia at the basal layers of the epidermis (AK I). Progression into invasive squamous cell carcinoma (iSCC) may occur following two main pathways, classical and differentiated. In the former, iSCC only occurs after involvement of the upper epidermal layers by atypical cells (AK III), while in the latter iSCC develops directly from AK I. In the anogenital mucosa, these two pathways are associated with differential expression of p53 and p16. OBJECTIVE: To explore differences between both pathways in the pathogenesis of AK, focusing on Ki67, p53, p16 and molecules that reveal epithelial-mesenchymal transition (EMT). METHODS: Tissue microarrays representative of superficial and deep portions of 80 consecutive iSCCs (53 DP/27CP) were studied immunohistochemically using antibodies against Ki67, p53, p16, vimentin, E-cadherin, ß-catenin and D2-40. The evaluation was performed by three researchers and the results compared to consensus. RESULTS: Invasive squamous cell carcinomas originated through the differentiated pathway exhibited significantly lower proliferative activity (Ki67) (30% vs 46%, P = 0.003) and significantly lower expression of vimentin (P < 0.001), E-cadherin (P < 0.001) and membranous ß-catenin (P < 0.001) than iSCCs developed through the classical pathway. The expression of E-cadherin and membranous ß-catenin was significantly correlated (Pearson's r = 0.386, Spearman's Rho < 0.001). There were no significant differences regarding the expressions of p53, p16 and D2-40. CONCLUSION: Epithelial-mesenchymal transition participates in transformation from AK I into iSCC (differentiated pathway), whereas a higher proliferative capacity facilitates intraepidermal extension in the classical pathway. Podoplanin, which is also involved in tumour invasion, does not seem to play a differential role in either pathway. Finally, the absence of differences in p53 and p16 expressions is at variance with other epithelia where the classical pathway is associated with human papillomavirus infection and can be explained by the fact that both AK pathways share identical mechanisms of actinic oncogenesis.

[Immune reconstitution and regulation following autologous hematopoietic transplantation using palifermin]. / Reconstitución de la inmunidad e inmunorregulación tras el trasplante autólogo de sangre periférica.

In the last decade there has been increasing awareness of the importance of thymus gland function in the reconstitution of host immunity following hematopoietic transplantation. A functional thymus contributes to foster T compartment reconstitution, with an increased diversity of T receptor rearrangement, and a more physiological distribution of the functional subpopulations. Palifermin, a keratinocyte growth factor (KGF) approved for reducing the incidence and severity of oral mucositis, has been proposed as a possible strategy for improving thymus function and immune reconstitution after hematopoietic transplantation. In vitro and animal models show palifermin to protect the thymus from chemo-/radiotherapy induced damage, increasing thymic production, accelerating immune reconstitution, improving response to vaccines, and reducing the incidence of graft-versus-host disease in animal models. To date, no studies have analyzed this possible application in humans. This study reports preliminary data on immune reconstitution in 50 autologous transplant recipients (30 treated with palifermin and 20 controls). The results suggest that palifermin at the doses and involving the regimens indicated for the prevention of oral mucositis has no effect upon thymus gland function in adult patients, and induces no changes in T immune recovery (either CD4 or CD8) or in the percentage of functional T subpopulations or T helper lymphocytes.