Increased p53 protein content of colorectal tumours correlates with poor survival

Abstract

Summary Allelic losses on the short arm of chromosome 17 occur frequently in colorectal cancers. Despite the existence of other common molecular events such as loss of the long arms of chromosomes 18 and 5, it has been demonstrated that the former has the greatest prognostic significance. Of the various genes mapping to the commonly deleted sequence, the best candidate as a 'target' seems to be the p53 antioncogene. We applied our An increasing body of evidence implicates the cellular antioncogene p53 in the development of human colorectal malignancy. In parallel to the discovery of the recurrent loss of the short arm of chromosome 17 (17p) by cytogenetic analysis (Muleris et al., 1985;, allelic losses were described, with probes specific for the short arm of chromosome 17, as well as for other chromosome segments (Fearon et al., 1987;Law et al., 1988; Delattre et al., 1989;Vogelstein et al., 1989;Fearon et al., 1990). The deletions on 17p were found to encompass a common region containing the p53 gene ) and mutations have been described in a number of cancer specimens The aim of the present study was to investigate the influence of the p53 content of cancer cells on the outcome of the disease. Two monoclonal antibodies (MAbs) recognising epitopes present on the wild-type protein (pAb 421: C-terminal and 1801: N-terminal) and the mutant-specific pAb 240 were used. Immunoreactivity was assayed on nuclear suspensions obtained by dissociation of surgical specimens of colorectal cancer and on the soluble fractions using a two point ELISA. Materials and methodsThe breast cancer cell line MDA-MB231 was cultured in a 1:1 mixture of DMEM and HAM F12 with 10% foetal calf serum (FCS) and 2% glutamine. A-431 cells (squamous carcinoma of the vulva) and HeLa cells (carcinoma of the cervix) were cultured in DMEM with 10% FCS. HL-60, myeloid leukaemia cells were cultured in RPMI 1640 with 20% FCS. In all cases exponentially growing cultures were harvested as previously described (Hammel et al., 1991) and stored in liquid nitrogen.A-431 and MDA-MB231 cells, which have been shown to contain homozygous p53 mutations Chen et al., 1990), were used as positive controls, HeLa cells, in which the p53 protein has been reported to be undetectable (Matlashewski et al., 1986), and HL60 cells that do not contain p53 mRNA consecutive to large deletions in the gene (Wolf & Rotter, 1985), were used as negative controls. Seventy-eight specimens of colorectal adenocarcinoma, operated between November 1985 and December 1989 and stored in our tumour bank were included in the study. All tissue fragments from the periphery of the tumours as well as macroscopically normal mucosa were obtained immediately after operation and stored at -80'C for short term conservation or in liquid nitrogen. These included 2 stage A, 29 stage

Increased serum p53 antibody levels indicate poor prognosis in patients with colorectal cancer

“…Studies in other tumour types support this notion (Crawford et al, 1982;Davidoff et al, 1992;Schlichtholtz et al, 1992;Winter et al, 1992;Mudenda et al, 1994). Loss of the p53 gene suppressor function has previously been reported in a range of human malignancies (Hollstein et al, 1991;Levine et al, 1991;Chang et al, 1995), including colorectal cancer (Levine et al, 1991;Remvikos et al, 1992;Sun et al, 1992;Vogelstein and Kinzler, 1992;Bell et al, 1993;Auvinen et al, 1994;Bosari et al, 1994;Dix et al, 1994a;Hamelin et al, 1994;Goh et al, 1995). A mutation in the p53 gene results in an accumulation of mutant p53 protein or in an overproduction of normal wild-type p53 protein (Dix et al, 1994a and b).…”

“…The result is thus in contrast to Houbiers et al (1995), who did not find an independent relation with prognosis in a multivariate analysis including the Dukes' stage but reported a weak association (P = 0.04) between high p53 serum levels and prognosis in patients with an early stage of the disease (Dukes' stage A). (Levine et al, 1991;Remvikos et al, 1992; Sun et al, 1992; Vogelstein and Kinzler, 1992;Bell et al, 1993;Auvinen et al, 1994;Bosari et al, 1994;Dix et al, 1994a;Hamelin et al, 1994;Goh et al, 1995). A mutation in the p53 gene results in an accumulation of mutant p53 protein or in an overproduction of normal wild-type p53 protein (Dix et al, 1994a and b).…”

“…Overexpression of the p53 protein is detectable in 30-70% of the tumours using immunohistochemistry. In some studies (Remvikos et al, 1992; Sun et al, 1992;Auvinen et al, 1994;Bosari et al, 1994) p53 protein overexpression has been shown to correlate to patient survival, while this has not been confirmed in other studies (Bell et al, 1993; Baas et al, 1994;Dix et al, 1994a;Morrin et al, 1994;Mulder et al, 1995;Kressner et al, 1996Poller et al, 1997).…”

“…Overexpression of the p53 protein is detectable in 30-70% of the tumours using immunohistochemistry. In some studies (Remvikos et al, 1992; Sun et al, 1992;Auvinen et al, 1994;Bosari et al, 1994) p53 protein overexpression has been shown to correlate to patient survival, while this has not been confirmed in other studies (Bell et al, 1993; Baas et al, 1994;Dix et al, 1994a;Morrin et al, 1994;Mulder et al, 1995;Kressner et al, 1996Poller et al, 1997).Mutant p53 protein, and other tumour-specific antigens, may be a target of the host's immune response (Schlichtholtz et al, 1992;Mudenda et al, 1994). Studies have shown that 9-26% of patients with different carcinomas have mounted a humoral immune response (antibodies) to abnormal p53 protein (Caron de Fromental et al, 1987;Levine et al, 1991;Angelopoulou et al, 1994).…”

p53 na prática clínica: sim ou não?

“…A detecção de mutação do p53 e a perda de alelo representam marcadores de prognóstico desfavorável (10,12,14) , todavia a utilidade da imunoistoquímica ainda é duvidosa e apresenta resultados conflitantes (2,9,11,13) . Apesar disso, geralmente ocorre forte associação entre imunoexpressão do p53 e análise gênica nos tumores retais, havendo falhas ao redor de 10% a 20% dos casos (18) .…”