Immunohistochemical expression of p16(INK4A) protein as a helpful marker of a subset of potentially malignant oral epithelial lesions: study on a series with long-term follow-up.
OBJECTIVE
To examine a group of lesions that progressed to oral squamous cell carcinoma (OSCC) to determine whether p16(INK4A) expression is an early finding during malignant transformation, and whether immunohistochemical evaluation of p16(INK4A) is an appropriate prognostic marker.


RESULTS
Twenty cases of OSCC were investigated. All cases had had a biopsy on the same site as OSCC performed at least 1year before OSCC (range 1-11years; mean 3.15±3.1years). Twenty specimens from normal oral mucosa served as controls. p16(INK4A) expression was evaluated by immunohistochemical analysis and cases showing >5% of stained cells were defined as 'positive'. All 20 control cases were negative for p16(INK4A) . Oral lesions were p16(INK4A) -positive in nine cases and negative in 11. No significant relationship was found between p16(INK4A) positivity and the presence/absence of dysplasia. Among OSCC, nine tumours showed p16(INK4A) positivity and 11 showed negativity. A significant relationship (χ(2)=7.1; P<0.01) was found between the presence/absence of p16(INK4A) staining in OSCC and the presence/absence of p16(INK4A) staining in lesions preceding OSCC.


CONCLUSIONS
p16(INK4A) immunohistochemistry has a potential role in detecting a subset of p16(INK4A) -positive lesions with malignant potential.
Montebugnoli
Lucio
L
Department of Oral Sciences, University of Bologna Unit of Maxillo-Facial Surgery, Bellaria Hospital, Bologna, Italy. lucio.montebugnoli@unibo.it
Cervellati
Fabio
F
Cocchi
Roberto
R
Farnedi
Anna
A
Pennesi
Maria Gabriella
MG
Flamminio
Federica
F
Foschini
Maria Pia
MP
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000473:pathology; D011230:Precancerous Conditions / Q000378:metabolism* / Q000473:pathology
D014408:Biomarkers, Tumor; D019941:Cyclin-Dependent Kinase Inhibitor p16