Mutated p53 as a molecular marker for the diagnosis of head and neck cancer.
In total, 10-30% of patients with head and neck squamous cell carcinoma (HNSCC) develop local recurrences despite seemingly adequate tumour resection. This may result from minimal residual cancer (MRC): small numbers of tumour cells left behind in the surgical margins, undetectable by routine histopathology. In recent studies, p53 mutations have been considered as selective and sensitive DNA markers of cancer cells. There are two potential problems in using mutated-p53 DNA as a marker. Firstly, p53 mutations occur early in progression and might therefore detect unresected precursor lesions besides tumour cells. Secondly, DNA is a very stable biomolecule that might lead to false-positive results. These two potential problems have been evaluated in this study. Fifty patients with a radical tumour resection were included, of whom 30 showed a p53 mutation in the primary tumour. Histopathologically tumour-free surgical margins were quantitatively analysed for mutated p53 by molecular diagnosis (plaque assay) and subsequent (immuno)histopathology. p53 mutated DNA was detected in the surgical margins of 19/30 patients. Immunohistochemistry confirmed the presence of small tumour foci in 2/19 mutated p53-positive cases. In 7/19 cases, the tumour-specific p53 mutation was found in unresected dysplastic mucosal precursor lesions. Moreover, in a number of cases small p53-immunostained patches were detected, but the mutations found were never tumour-related. By screening contralateral exfoliated cells and plaque assays on RNA it was shown that detection of mutated-p53 DNA is prone to false-positive results. In conclusion, using p53 mutations as a marker, both MRC and unresected mutated p53-positive mucosal precursor lesions are detected within surgical margins. Molecular assessment of surgical margins using p53 mutations enables the selection of HNSCC patients at high risk for tumour recurrence, but tumour RNA seems at present to be a more specific biomolecule for analysis than tumour DNA.
van Houten
Viola M M
VM
Department of Otolaryngology/Head and Neck Surgery, Vrije Universiteit Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
Tabor
Maarten P
MP
van den Brekel
Michiel W M
MW
Kummer
J Alain
JA
Denkers
Fedor
F
Dijkstra
Janny
J
Leemans
René
R
van der Waal
Isaäc
I
Snow
Gordon B
GB
Brakenhoff
Ruud H
RH
D014408:Biomarkers, Tumor / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics; D005189:False Positive Reactions; D016158:Genes, p53; D005819:Genetic Markers; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D006801:Humans; D007124:Immunoenzyme Techniques; D009154:Mutation; D009364:Neoplasm Recurrence, Local / Q000235:genetics; D018365:Neoplasm, Residual; D011230:Precancerous Conditions / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D005819:Genetic Markers; D012334:RNA, Neoplasm; D016159:Tumor Suppressor Protein p53