CORRELATION OF P21 EXPRESSION IN HEAD AND NECK SQUAMOUS CELL CARCINOMA WITH CLINICOPATHOLOGIC AND PROGNOSTIC PARAMETERS

Abstract

Purpose: Head and neck tumours include tumours of nose, paranasal sinuses, oropharynx, larynx and mouth. Squamous cell carcinoma (SCC) is the most common head and neck malignant tumour which accounts for 90% of head and neck malignant tumours. p21 is an important immunohistochemical marker which has signi cant role in predicting prognosis of head and neck SCC (HNSCC). Increased p21 expression in HNSCC is associated with bad prognosis in terms of increased risk of nodal metastasis, increased rate of recurrence and decreased survival rate. The purpose of this study was to evaluate the expression of p21 in HNSCC with various clinicopathologic and prognostic parametres. Materials and Methods: A total of 110 patients (n = 110) of HNSCC (oral cavity n = 98 and laryngeal tumours n = 12) were included in the study which were diagnosed and treated between January 2008 and January 2011 at a tertiary care centre in Pakistan. Mean age was 51 years (age range 15–78). 65 (59%) were male and 45 (41%) were female. Tumours were classi ed as p21 positive when ≥10% tumour cells were immunoreactive for p21. p21 expression was noted and correlated with T-stage, nodal metastasis, perineural and depth of invasion, recurrence and 2-year survival rate. Results: Of 110 cases, p21-positive cases were 88 (80%) compared to 22 (20%) negative. T1–T2 tumours with p21 expression were 59 (67.04%) while 17 cases (77.27%) had negative for p21 (P = 0.44). Amongst T3–T4, 29 cases showed p21 expression (32.96%) while 5 cases (22.73%) were negative (P = 0.44). Nodal metastasis was seen in 51 cases (57.95%) with p21 positivity as compared to 4 cases (18.8%) with no p21 expression (P = 0.0015). Perineural invasion was seen in 15 carcinomas (17.04%) having p21 positivity and 1 case (4.54%) with p21 negativity (P = 0.18). 48 cases (54.54%) had depth of invasion >1 cm with positive p21 as compared to 4 cases (18.18%) without (P value = 0.0035). 39 cases (44.31%) showed recurrence along with p21 expression while 3 cases (13.63%) showed recurrence without (P = 0.0076). 2-year survival rate was 56.81% (n = 88) in p21 positive cases, whereas it was 90.90% (n = 20) those with negative p21 (P = 0.0026). Conclusion: Positive p21 expression in HNSCC correlates with intermediate grade, late stage, increased nodal metastasis, tumour recurrence and decreased survival. p21 should be considered as an important prognostic and predictive marker in HNSCC to detect tumours at early stage and to improve therapy and prognosis. Key words: Head and neck squamous cell carcinoma, lymph node metastasis, p21, recurrence, survival rate