Decreased expression of thymidine phosphorylase/platelet‐derived endothelial cell growth factor in basal cell carcinomas

Abstract

Thymidine phosphorylase (TP)/platelet-derived endothelial cell growth factor is associated with tumor angiogenesis. We evaluated the TP mRNA and protein expression in basal cell carcinomas (BCC) and in various skin tumors including numerous BCC histological simulants. Immunohistochemistry was performed on 99 paraffin sections of formalin-fixed skin tumors using monoclonal antibodies (mAb) against TP. TP mRNA levels were measured by real time RT-PCR in whole BCCs (wBCC) and laser capture microdissected (LCM) BCC tumor cells. TP immunostaining was negative in all BCC variants and in most of the benign trichogeneic tumors studied. By contrast, TP was constantly immunodetected in actinic keratosis (AK), squamous cell carcinomas (SCC), syringomatous carcinomas (SC), basosquamous carcinomas (BSC) and melanomas. TP mRNA levels were low and statistically not different in wBCC and normal skin but were strongly downregulated in LCM-BCC as compared with LCM-normal epidermis. We concluded that (i) anti-TP mAb is an useful marker to differentiate BCC from AK, SCC, BSC and SC but not from trichoblastic tumors, (ii) the lack of TP protein expression in BCC tumoral cells is linked to transcriptional regulatory mechanisms, (iii) the low TP mRNA levels in whole BCC may be related to the low intra-tumoral microvessel density, the slow growth and the very low metastatic potential of these tumors.

Proteolytic activity and expression of the 20S proteasome are increased in psoriasis lesional skin

“…Paraffin‐embedded tissue sections (7 μm) were used for immunoperoxidase staining as previously described 20 . Primary antibodies were all purchased from Affiniti Research Products (Exeter, U.K.) and directed against 20S subunits pan‐α [monoclonal antibody (mAb) MCP231, 1 : 500], α6 (mAb MCP20, 1 : 500), β1 (= Y, mAb MCP421, 1 : 100), β2 (= Z, mAb MCP168, 1 : 100), β1i (mAb LMP2, 1 : 100), β5i (mAb LMP7, 1 : 100) and against the 19S subunit rpt5 [= S6a, polyclonal antibody (pAb), 1 : 500].…”

The proteasome maturation protein POMP increases proteasome assembly and activity in psoriatic lesional skin

“…Paraffin-embedded skin biopsies sections were prepared and stained using a peroxidase-based protocol as previously described [17].…”

Gene expression analysis of immunostained endothelial cells isolated from formaldehyde‐fixated paraffin embedded tumors using laser capture microdissection—A technical report

“…LCM is normally used to demonstrate the presence of specific gene transcripts in cryosectioned tissues (Cristobal et al, 2004(Cristobal et al, , 2005. LCM of immunostained frozen tissue sections has been used successfully for gene expression analysis (Fend et al, 1999;Stoebner et al, 2008). We have also reported that gene expression of some antigen presenting cell-related molecules, such as HLA-DR a-chain, CD83, and CD86, can be analyzed in LCM-retrieved HLA-DR-expressing cells from immunostained frozen tissue sections (Kaneko et al, 2008).…”