Suprabasal p53 immunoexpression is strongly associated with high grade dysplasia and risk for malignant transformation in potentially malignant oral lesions from Northern Ireland

Table 1A Clinicopathological data of potentially malignant oral lesions and respective oral squamous cell carcinomas

Biopsy: lower case letter (n), potentially malignant lesion; capital (N), carcinoma. Tob/Alc: (patients� tobacco smoking/alcohol drinking habits): 0, not known; 1, non-smoker/non-drinker; 2, less than 10 cigarettes a day/less than 2 units of alcohol a day; 3, between 10 and 20 cigarettes a day/between 2 and 4 alcohol units a day; 4, more than 20 cigarettes a day/more than 4 units of alcohol a day; PS, pipe smoker; Ex , ex-smoker. Diagnosis: PML, potentially malignant lesion; *, erythroleucoplakia; SCC, squamous cell carcinoma. Location: FM, floor of mouth; BM, buccal mucosa; T, tongue; HP, hard palate; RMP, retromolar pad; Alv, alveolus; AP, anterior pillar of fauces; �, in continuity with potentially malignant lesion analysed. Biopsy: INC, incisional; EXC, excisional. Dysplasia: 1, No or mild dysplasia; 2, moderate or severe dysplasia; �, moderate or severe dysplasia present in the histological section but absent from its margins. Progression to carcinoma: NP, no progression to carcinoma during follow up (controls); P, progression to carcinoma during follow up (cases); Follow up: time between biopsy and development of SCC (when applicable) or last control visit; p53 immunohistochemistry (IHC): Neg, negative; Bas, basal p53 staining; SB, (basal and) suprabasal p53 staining; SB�, suprabasal p53 staining present in the histological section but absent from its margins; +, less than 25% immunopositive tumour cells; ++, more than 25% immunopositive tumour cells; NA, material not available for analysis.