High tPA-expression in primary melanoma of the limb correlates with good prognosis

To investigate whether the course of primary melanoma disease correlates with expression of the various components of the proteolytic plasminogen activation (PA) system, immunohistochemical stainings for activators of plasminogen (tissue type (tPA) and urokinase type (uPA)), inhibitors of plasminogen activation (type 1 (PAI-1) and type 2 (PAI-2)) and the receptor for uPA (uPAR) were performed on 214 routinely processed melanoma lesions. All lesions were primary cutaneous melanomas, minimally 1.5 mm thick, and derived from patients with only local disease at the moment of diagnosis (clinically stage II (T 3–4 N 0 M 0), American Joint Committee on Cancer). Median patient follow-up was 6.1 years. Single variables as immunohistochemical staining results (extent of tumour cell staining, pattern of tumour cell staining and for some components also staining of stromal cells), histopathological and clinical parameters as well as treatment variables were analysed in order to assess their prognostic importance, in terms of time to recurrence, time to distant metastasis and duration of survival. The extent of tPA tumour cell positivity, categorized as 0–5%, 6–50% and 51–100%, appeared to be of importance for these end-points. Lesions with 51–100% tPA-positive tumour cells were found to have the best prognosis, whereas lesions with 6–50% tPA-positive tumour cells had the worst. Moreover, the prognostic significance of Breslow thickness, microscopic ulceration and sex was confirmed in this study. Multivariate analyses, incorporating these relevant factors, showed that the extent of tPA tumour cell positivity was an independent prognostic factor for distant metastasis-free interval (P= 0.012) and for the duration of survival (P= 0.043). © 2000 CancerResearch Campaig

The time-dependent expression of keratins 5 and 13 during the reepithelialization of human skin wounds

The time-dependent reepithelialization of 55 human surgical skin wounds with a wound age between 8h and more than 2 months was investigated by the immunohistochemical localization of cytokeratins 5 and 13. A complete, rebuilt epidermal layer over the wound area was first detectable in a 5-day-old wound, while all wounds of more than 18 days duration contained a completely reepithelialized wound area. Between 5 and 18 days the basal layer of keratinocytes showed — in contrast to normal skin — only some cells positive for cytokeratin 5. In some, but not all lesions with a wound age of 13 days or more, a basal cell layer completely staining for cytokeratin 5 was demonstrable. This staining pattern was found in all skin wounds with a wound age of more than 23 days. The immunohistochemical detection of cytokeratin 13 which can be observed regularly in non-cornifying squamous epithelia provides no information for the time-estimation of human skin wounds, since no significant temporary expression of this polypeptide seems to occur during the healing of human skin wounds

Dietary factors, genetic susceptibility and somatic mutations in colorectal cancer: a prospective study.

Item does not contain fulltex

Transcription of the MAGE-1 gene and the methylation status of its Ets binding promoter elements: a quantitative analysis in melanoma cell lines using a real-time polymerase chain reaction technique

The human MAGE gene family comprises at least 12 highly homologous genes. This makes it very difficult to assess expression of a single member quantitatively by means of Northern blotting. In order to investigate expression of the MAGE-1 gene quantitatively we therefore used the recently developed real-time polymerase chain reaction (PCR), a novel fluorescence-based quantitative PCR technique. This powerful technique enables detection of expression levels which differ by as much as a factor of 10(5) in magnitude. MAGE-1 expression is known to correlate with demethylated status of the Ets binding sites of its promoter. In a panel of 19 melanoma and nine non-melanoma cell lines we were able to confirm the relationship between MAGE-1 expression and demethylation of the Ets binding promoter region. Five cell lines, however, showed only very slight expression, while the two essential Ets promoter elements were largely demethylated. Earlier studies have shown that treatment of MAGE-1-negative cell lines with the demethylating agent 5-aza-2'-deoxycytidine (DAC) is sufficient to induce MAGE-1 expression. We were able to induce clear MAGE-1 expression in two of the non-expressing cell lines by incubation with DAC, although this expression did not reach very high levels. Consistent with this low level of induction is the observation that the Ets binding sites of the MAGE-1 promoter were not completely demethylated in the DAC-treated cell populations. In conclusion, we show in this study that the real-time PCR technique is a very useful tool for the quantification of expression of highly homologous genes. (C) 1999 Lippincott Williams & Wilkins