TUSC2 and lung cancer: While studies on lung cancer cell lines revealed a limited (~4%) frequency of mutations in the TUSC2 gene [10,16] and infrequent methylation of its promoter [16], large-scale analysis of TUSC2 expression in lung cancers and in bronchial squamous metaplastic and dysplastic lesions have revealed significantly lower levels of TUSC2 as compared to normal hyperplastic epithelia [30].