Sequential deletions in both arms of chromosome 9 are associated with the development of head and neck squamous cell carcinoma in Indian patients

Abstract

In the deletion mapping of chromosome (chr) 9 in head and neck lesions of the Indian patient population by microsatellite markers, we have identified four discrete areas (D1-D4) with high loss of heterozygosities (LOHs) viz. 9p24-p23 (D1), 9p22-p21 (D2), 9q11-q13 (D3) and 9q22.3 (D4) regions. The deletions in D2 and D4 regions were suggested to be essential for the development of dysplastic lesions of head and neck, whereas the deletions in D1 and D3 regions were responsible for progression of the dysplastic lesions to early invasive head and neck squamous cell carcinoma (HNSCC). The microsatellite size alterations (MAs) were observed in the chromosomal 9pter-p23, 9p22-p21(D2), 9q13 and 9q21.1-q21.2 regions with gradual increase during progression of the tumor. Additional chromosomal alterations like loss of normal copy of chr.9 and biallelic alterations were also seen in our samples. There is a correlation between HPV infection with TNM stages, histopathological grades and LOHs at D1 and D4 regions. Whereas tobacco habit is associated with the occurrence of LOHs at D1 and LOHs/MAs at D2 region.