Micronuclei and p53 accumulation in preneoplastic and malignant lesions of the head and neck

Abstract

No single biomarker can predict the risk for malignant transformation of precancerous lesions of the head and neck. Micronucleus frequency, nuclear p53 accumulation and mitotic index were determined in proliferating basal cells using paraffin-embedded specimens from normal, dysplastic and malignant tissues. p53 accumulation was detected by immunohistochemistry using pAb 1081 and pAb 240 antibodies. Micronuclei were scored in the same cell population and classified for the presence/ absence of p53 accumulation in the main nucleus. Fifty-three carcinomas and 15 precancerous lesions were studied. Both micronuclei and p53 accumulation were found in precancerous lesions, suggesting that they are early events in head and neck squamous cell carcinoma progression. The two biomarkers were not related to each other: indeed, micronucleus frequency was higher in p53-negative than in p53-positive cells. Three patients with precancerous lesions later developed carcinomas; all three cases showed high frequencies of both micronuclei and cells accumulating p53 protein.

Regression of progestin-accelerated 7,12-dimethylbenz[a]anthracene-induced mammary tumors in Sprague–Dawley rats by p53 reactivation and induction of massive apoptosis: a pilot study

“…Here, the expression of mutant p53 was examined in MPA-accelerated and non-MPA-accelerated DMBA-induced tumors. This experiment utilized a conformation-specific antibody, PAb240, which recognizes mutant p53 but not wild-type p53 (Bykov et al 2002, Delfino et al 2002. The results show that six out of eight (75%) MPA-accelerated tumors express mutant p53 (predominantly in the nucleus), while non-MPA-accelerated DMBA-induced tumors do not express mutant p53 (Fig.…”

“…Tissues were quenched with 3% hydrogen peroxide, rinsed, and incubated with 5% BSA to minimize non-specific antibody binding. The sections were then incubated with the antibody that recognized mutant p53 (PAb240 at 1:10; Calbiochem, San Diego, CA, USA) for 60 min at room temperature (Delfino et al 2002). Control frozen sections of BT-474 and MCF human breast cancer cells (ATCC) were similarly probed with PAb240.…”

Correlação entre a evolução clínica e a freqüência de micronúcleos em células de pacientes portadores de carcinomas orais e da orofaringe

“…Por outro lado, o teste do micronúcleo, por ser de baixo custo e acessí-vel mesmo com pouco aparato tecnológico, continua sendo testado como um biomarcador para detecção de pacientes com risco de desenvolvimento de câncer e também para monitorar a ação de quimioprotetores 16,17 . O grupo de pacientes que poderá ser particularmente beneficiado com este monitoramento é aquele composto por indivíduos etilistas e tabagistas crônicos que persistem com o hábi-to mesmo após já terem apresentado uma primeira neoplasia primitiva da mucosa das vias áreas digestivas superiores.…”

Korelasi antara jumlah mikronukleus dan ekspresi 8-oxo-dG akibat paparan radiografi panoramic (The correlation of micronucleus formation and 8-oxo-dG expression due to the panoramic radiography exposure)

“…7 Peningkatan frekuensi mikronukleus pada mukosa normal di sekitar lesi berpotensi menjadi lesi prekanker akibat terjadinya ketidakstabilan kromosom merupakan mekanisme penting dalam perkembangan kanker. 8 Mikronukleus bersifat semipermanen karena akan menetap dalam jangka waktu sekitar 1-2 kali pembelahan. Timbulnya mikronukleus sering diyakini sebagai marker pada tahap dini mekanisme karsinogenesis pada sel yang terlibat.…”

“…Kedua parameter ini menunjukkan perubahan yang berkaitan dengan preneoplastik yang diyakini sebagai paramater untuk penilaian respons terhadap agen spesifik. 8 . Tabel 1 14 Kerusakan berupa DNA adduct ini meningkatkan kemungkinan mutasi genetik dalam sel yang memicu proses karsinogenesis.…”