The expression of interleukin 10 (IL-10) mRNA in human malignant melanoma was investigated by reverse transcriptase polymerase chain reaction analysis. Selective expression of IL-10 mRNA in tissues of primary melanomas and melanoma metastases was found in comparison with normal skin. In addition, strong expression of IL-10 mRNA and of biologically active IL-10 was detected in 3 out of 13 melanoma cell lines. Normal melanocytes consistently expressed low levels of IL-10 mRNA but did not produce detectable IL-10 protein, nor did keratinocytes or fibroblasts. The production of biologically active IL-10 by melanoma cell lines suggests that IL-10 mRNA in melanoma lesions may derive at least in part from the tumour cells themselves. Tumour-infiltrating cells, however, could also be a source of IL-10 in melanoma tissues. The presence of IL-10 in melanoma lesions may contribute to the postulated 'paralysis' of an anti-melanoma immune response. Images Figure 1 Figure 2

Background: In Greece where primary health care services are not fully developed, patients with simple or minor conditions have to attend to hospitals to be treated. We analysed the data of patients with cutaneous disorders attending the tertiary referral hospital on the Island of Crete, with the aim to identify the most common conditions that patients complain of, in order to define the areas where the education of General Practitioners in Dermatology must focus.

The oncogenic potential of translation initiation factors (eIF-4E and eIF-2a) has been described in previous studies leading to the definition of translational oncogenes. Two previously isolated cDNA clones, expressed differently in human melanoma cells and normal human melanocytes, were identified in this study as coding for the translation initiation factor eIF-4AI. Northern-blot analysis revealed consistent overexpression of eIF-4AI mRNA in a panel of 14 melanoma cell lines (on an average 5.6 times higher than in cultures of normal human melanocytes). In contrast, the mRNAs of the other group-4 translation initiation factors (eIF-4A2, eIF-4B, eIF-4E and eIF-4g) were less and not consistently elevated. Control of protein synthesis is known to be a cellular mechanism necessary for saving energy resources and for rapidly responding to changing growth requirements. It is predominantly exerted at the level of translation initiation. This process can be subdivided into 5 steps corresponding to 5 groups of translation initiation factors (Rhoads, 1993). Two steps were shown to be of major importance for control: (i) formation of the 43S pre-initiation complex by binding of the initiator-tRNA to the 40S ribosomal subunit (group-2 factors), and (ii) subsequent binding between preinitiation complex and mRNA in order to form the initiation complex (group-4 factors).Group 4 consists of 5 factors for which the human cDNA sequences have been determined: eIF-4A1 (Kim et al., 1993), eIF-4A2 (Sudo et al., 1995), eIF-4B (Milburn et al., 1990), eIF-4E (Rychlik et al., 1987) and eIF-4g (Yan et al., 1992. The 2 factors eIF-4A1 and eIF-4A2 are homologous to each other and share 91% homology (Nielsen and Trachsel, 1988). It was further shown that only one copy of either eIF4A1 or eIF4A2 is needed for formation of the translation initiation complex and that both factors are interchangeable (Yoder-Hill et al., 1993). According to a present model, a complex of eIF-4A, eIF-4E and eIF-4g binds the mRNA cap, and the mRNA secondary structure is then unwound by several eIF-4A and eIF-4B molecules, preparing it for binding to the 43S pre-initiation complex. Supporting this model, eIF-4A was shown to have RNA helicase activities (Ray et al., 1985).For identifying specifically regulated genes in human melanoma cells, several clones had been isolated from a melanoma cell cDNA library by differential screening, and were shown to be regulated in the 4 melanoma cell lines IGR39, M5, MEWO and SKMEL13. Two up-regulated clones were identified as b-tubulin and the glycolytic enzyme enolase, respectively, and 2 down-regulated ones were shown to correspond to the tyrosinase-related proteins TRP1 and TRP2, respectively (Eberle et al., 1995a,b). This study will report on the identification of the up-regulated clone 25F5 as coding for eIF-4A1 and present a comprehensive analysis of the expression of all group-4 translation initiation factors in a large panel of human melanoma cell lines, normal human melanocytes, and cultures of congenital melanocytic nev...

Reverse transcriptase polymerase chain reaction for the detection of tyrosinase-mRNA-positive cells in peripheral blood of melanoma patients, as a possible marker of hematogenous dissemination, has demonstrated varying detection rates. This study examined the sensitivity and reproducibility of the technique using a protocol of multiple polymerase chain reaction to determine circulating melanocytic cells. For each of the 123 melanoma patients included in this study, four nested polymerase chain reactions were performed from two blood specimens requiring both polymerase chain reactions from at least one blood sample to be positive to consider a patient as positive. Thus, a definitive result was obtained in 98% of the cases, whereas only 1.6% lacked conclusive findings. Thus, we found a correlation between the tyrosinase detection rate and the clinical stage. Circulating tyrosinase-mRNA-positive cells were detected in 13% of patients with primary tumor, 17% with regional skin/lymph node metastasis, and 44% with distant metastasis. Positivity also correlated with known melanoma progression markers such as gender, tumor thickness, and histologic type. Positive results were obtained more frequently in (i) men compared with women, (ii) patients with thick primary melanomas (> 4 mm: 38%) compared with those with thinner tumors (1.1-4 mm, 22%; < or = 1 mm, 5%), and (iii) patients with nonclassifiable (38%), nodular (34%), and occult primary melanomas (30%) compared with those with acrolentiginous (17%), superficial spreading (9%), or lentigo maligna melanoma (0%). These findings suggest that detection of tyrosinase-mRNA-positive cells in peripheral blood is not an adequate marker for identifying melanoma patients with distant metastasis. Reverse transcriptase polymerase chain positivity in early melanoma stages, however, as corresponding to other prognostic parameters, may indicate increased risk for the development of hematogenous metastasis and may be of value as a progression marker.

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