Increased expression and altered intracellular distribution of adhesion/growth-regulatory lectins galectins-1 and -7 during tumour progression in hypopharyngeal and laryngeal squamous cell carcinomas

Aims:  To examine the level of expression of the pleiotropic regulators galectins-1 and -7 in relation to neoplastic progression of hypopharyngeal (HSCCs) and laryngeal (LSCC s ) squamous cell carcinomas.
Methods and results:  The presence of galectins-1 and -7 was investigated using quantitative immunohistochemistry in (i) a series of 78 HSCCs by comparison with 17 normal epithelia (N_E), 26 low-grade dysplasia (low_D) and 27 high-grade dysplasia (high_D) and (ii) a series of 56 LSCCs by comparison with 50 N_E, 23 low_D and 29 high_D. Galectin-1 positivity expressed as a percentage of cells was significantly higher in carcinomas (HSCCs and LSCCs) than in N_E, low _ D or high _ D ( P  < 10⁻⁶). Galectin-7 expression was elevated in low _ D ( P  = 0.0004) compared with N_E and in carcinomas (HSCC) compared with high _ D ( P  = 0.0002). Tumour progression from high_D to carcinomas was associated with a shift of galectin-1 localization from the nucleus towards the cytoplasm. Increased expression of galectin-7 in dysplasias was accompanied by a shift from the cytoplasmic compartment (N_E) to the nucleus (low_D and high_D).
Conclusions:  Our data reveal an association between the level of presence of galectins-1 and -7 and neoplastic progression of HSCCs and LSCCs. Moreover, inverse shifts between nuclear and cytoplasmic positivity intimating functional divergence were detected.