TRANSCRIPTIONAL ACTIVATION OF HMGI-C IN 3 PULMONARY HAMARTOMAS EACH WITH A DER(14) T(12-14) AS THE SOLE CYTOGENETIC ABNORMALITY

Aberrations involving the chromosomal region 12q14-15 are non-random c ytogenetic abnormalities in many benign tumors, e.g. pulmonary chondro id hamartomas (PCH). Recently, we identified rearrangements of the HMG I-C gene within the third or fourth intron as the molecular mechanism underlying most of these chromosomal aberrations. Herein we report our FISH and RACE studies on three PCHs each showing a rare variant type of the translocation t(12;14)(q14-15;q24) with presence of two normal chromosomes 12 and a der(14) but missing the der(12). The results reve aled that in all three cases the breakpoint is located 5' to HMGI-C, s uggesting that besides intragenic rearrangements also transcriptional activation of the gene can initiate tumor growth.