Abstract: Objective To investigate the IgG expression in laryngeal squamous cell carcinoma (LSCC), compare it with IgG of B lymphocytic origin, and explore its possible clinical significance. Methods IgG expression in LSCC cells was detected with immunohistochemistry and in situ hybridization. Heavy chains and light chains of IgG were detected with laser guided microdissection coupled with RT-PCR. VDJ rearrangement of IgG heavy chain variable region 1 was assessed with sequencing and BLAST. The correlation between IgG expression and the pathological parameters was assessed by statistics. Results Igγ, Igκ and Igλ were detected in the same cell of LSCC, characteristic of peripheral distribution at cancer nests. IGHG1 mRNA expressions were co-localized with Igγ in the cancer cells. The mRNAs of IGHG1, Igκ and Igλ were detected in LSCC cells by RT-PCR. VDJ rearrangement occurred when the heavy chains were synthesized, but it presented a monotonous pattern and a small quantity of point mutations, the ratios of which were 2.03%-3.67%. IgG expressions were much stronger in the cases of low differentiation, Ⅲ-Ⅳ stages or lymph node metastasis. Conclusion IgG is expressed in LSCC cells, which has unique VDJ rearrangement different from IgG of B lymphocytic origin. IgG derived from LSCC cells is significantly associated with stages, grades and lymph node metastasis.

Key words: Immunoglobulin G, Laryngeal squamous cell carcinoma, Clinical stage, Pathological grade