Gene: [13q14/DBM] tumor supressor DBM (putative; disrupted in B-cell malignancy); B-cell malignancy, low grade; leukemia, chronic lymphocytic, B-cell;

COM	[1] The DBM was identified as a locus in the region of D13S25, whose inactivation contributes to the initiation or progression of low grade B-cell malignancy (Brown-1993). Brown et al. showed that this locus is at least 530 kb telomeric to RB1 (GEM:13q142/RB1). [2] On the basis of mapping data, allelic loss analyses at 13q14 using CLL tumor samples allowed narrowing of the genomic segment encompassing the putative CLL gene to less than 300 kb (Kalachikov-1997). [3] Panayiotidis et al. support previous findings that the 13q14.3, and not the 13q12 region (see GEM:13q1/BRCA2), is the major site of candidate tumour suppressor gene(s) in CLL (Panayiotidis-1997). [4] Newcomb-1995 found that inactivation of the tumor suppressor genes p53 (GEM:17p131/TP53) and DBM may be mutually exclusive, thus providing alternate pathways for tumor development in B-CLL patients."
ASS	Roughly 25% of human B-cell chronic lymphocytic leukemias (CLLs) are characterized by a chromosomal lesion involving 13q14 (Chapman-1994)."
REF	ABR,LOC,LIN,ASS,PAT "Brown AG &: Nature Genet, 3, 67-72, 1993 ABR,PAT,ASS "Chapman RM &: Oncogene, 9, 1289-1293, 1994 PAT,LIN "Hawthorn LA &: Oncogene, 8, 1415-1419, 1993 LOC,LIN,MAF "Kalachikov S &: Genomics, 42, 369-377, 1997 PAT,ASS,FAG "Newcomb EW &: Mol Carcinog, 14, 141-146, 1995 ABR,PAT,LOC,LIN "Panayiotidis P &: Brit J Haematol, 97, 844-847, 1997
KEY	imm, onc
CLA	coding, basic
LOC	13 q14
MIM	MIM: 109543