ISSN:
0730-2312
Schlagwort(e):
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Biologie
,
Chemie und Pharmazie
,
Medizin
Notizen:
In human mammary carcinoma, positive immunohistochemical staining for p53 protein is not always indicative of mutation in the p53 gene. Although positive staining is seen in excess of 50% of tumours, mutations have been found in only some 20% of cases. In this presentation, positive p53 staining in mammary carcinomas will be related to the presence and absence of mutation and other possible underlying mechanisms.In some positively stained tumours a mutation has been found. In others, no mutation has been demonstrated and apart from possible stabilisation by a protein such as MDM2, there are alternative underlying mechanisms for this discrepancy. Wild type p53 is elevated in response to DNA damage. This effect can be seen in patients given pre-operative chemotherapy and in cell lines irradiated with UV light and with x-rays. Strong positive staining in scattered nuclei has been found in cell lines with activated ras and myc genes. We postulate that this may also be the reason for similar patterns observed in human tumours.Comparable mechanisms may be active in inherited cancers. Although positive p53 staining in some Li-Fraumeni syndrome patients is associated with mutation, in other Li-Fraumeni-like families, no mutation has been found despite positive staining in tumour and normal tissues.Whatever the mechanism underlying the stabilisation of the protein, increased expression of p53 protein in the majority of tumour cells appears to be associated with poor prognosis in breast carcinoma.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jcb.240531147
