There are five hotspots of frequent deletions indicating that several putative tumor suppressor genes on chromosome 6 are involved in the development of thymic epithelial tumor [ 8, 22, 23].
For ICE Hptfs4 islands, we found certain deletions that are more frequent.
Using a short time interval (1 2 h) between radiation exposure and sampling, the metaphase cells (blocked with colcemid) collected are those that were in the G2-phase of the cell cycle at the time of exposure and show frequent chromatid breaks (discontinuities or terminal deletions) that have been shown to be induced as a linear function of radiation dose (Bryant, 1998).
The much lower A frequency following TpG sites compared to that in fish genes is perhaps due to more frequent insertions or deletions that shift reading-frames of the sea squirt genes.
The most frequent, found in all 8 clones for patient 2 and in 4 of 11 clones for patient 1, are deletions that surround the germ line single nucleotide deletion.
The chromosomal pgm locus is prone to relatively frequent deletions and internal rearrangements that result in loss of the Hms or pigmentation segment, the HPI containing the Ybt operons, or both [16].
Actually, it has been reported that frequent deletions of miRNA genes miR15 and miR16 occur on patients with chronic lymphocytic leukaemia, suggesting a possible role for these miRNAs in the generation of this type of cancer [ 28].
As colorectal cancer is also characterized by frequent deletions or translocations of 1p36 [11], we believe that our present data is a first step in the elucidation of the potential tumor suppressive properties of NBPF1.
Alternatively, such a distribution could result from the sporadic accumulation of large insertions in IGRs that are gradually eroded by more frequent deletions.
Frequent deletions of Wnt and other Wnt signaling pathway genes suggest that the Wnt signaling pathway is genetically inactivated in human osteosarcoma.
