FHIT mRNA expression in thymoma

Aims: The FHIT gene is located at 3p14.2 a region frequently lost in multiple tumour types. Loss of FHIT expression has been found to occur frequently in multiple tumour types. We wished to investigate that FHIT mRNA levels in a series of thymomas. Methods: Expression of FHIT messenger ribonucleic acid (RNA) was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) using a LightCycler in 49 thymomas and 11 adjacent histologically normal thymus samples from patients. Results: FHIT transcripts in tumour samples (28.6±35.8) at levels significantly lower than those in normal thymus samples (573.9±1028.0, p=0.001). No relationship was seen between FHIT gene expression and age, gender, or pathological thymoma subtypes. FHIT mRNA expression in invasive thymomas (stage II–IV, 34.5±39.2) was significantly higher than that in stage I thymomas (20.7±29.7, p=0.01). Immunohistochemistry showed that p21 protein positive thymoma had a tendency towards higher FHIT gene expression than in p21 negative thymoma. Conclusions: Decreased FHIT expression might be seen in early stage thymoma, suggesting that loss of FHIT expression may associate with tumorigenesis of thymoma.