6p21.31

HMG-R,HMGA1A,HMGIY

Pulmonary chondroid hamartoma

benign tumor of the lung

good

the most frequent rearrangement is a reciprocal balanced translocation t(6;14) (p21.3; q24); the rearrangement between chromosomes 6 and 14 can sometimes be complex, identifiable by FISH; molecular results also suggest that the translocations might be more complex than shown by conventional cytogenetics, with the presence of additional cryptic rearrangements; translocations involving partner chromosomes other than chromosome 14, such as chromosomes 1, 3, 4, 5, 10, 12, 17 have also been reported; inversions inv(6)(p21q21) or inv(6)(p21.3q26) have been described

in most cases, the breakpoint was extragenic, located within a 80 kb region 3 of HMGIY; aberrant transcripts with truncation of sequences from the 3 UTR have been described; in only one case with inversion inv(6)(p21q21), a hybrid intragenic fusion has been reported: HMGIY was fused to the LAMA4 (laminin a4 chain) gene

the HMGIY-LAMA4 resulted from the fusion of the three HMGIY DNA-binding domains with the LAMA4 EGF-like domain

the exact role of HMGI(Y)-LAMA4 fusion is not established yet

Lipomas

benign adipocyte tumors

good

a small subset (5-8%) of ordinary lipomas is characterized by 6p21 rearrangements, the most frequent of which being a reciprocal translocation t(3;6)(q28;p21); in contrast to other benign mesenchymal tumors with 6p21 rearrangement, there is no evidence of HMGIY rearrangements in ordinary lipomas yet; however, to be noticed, the breakpoint on 6p21 was shown to be located whithin a 80 kb region surrounding HMGIY in one lipoma case and HMGIY expression was correlated with 6p rearrangements in two ordinary lipomas and two spindle cell lipomas

Uterine leiomyoma

benign mesenchymal tumors

good

approximately 40% of uterine leiomyomas present structural chromosomal rearrangements, 5% of which involve 6p abnormalities; they include t(1;6)(q23;p21), t(6;14)(p21;q24) and t(6;10)(p21;q22) as well as inversions and translocations involving other chromosomal partners; the rearrangements are sometimes complex, only identifiable by FISH analysis

no hybrid gene has been described yet; as for other mesenchymal tumors, the breakpoint was extragenic, located within a 80 kb region 3 of HMGIY; one case of aberrant transcript with truncation of 1295 bp from the 3 UTR has been described

HMGIY mRNA and protein levels do not always correlate, suggesting that post-transcriptional mechanisms are involved in the regulation of HMGIY

Endometrial polyps

uterine benign tumors

good

several chromosomal abnormalities involving the 6p21.3 region, including translocations, deletions, inversions have been described; various chromosomal partner regions, such as 14q24, 20q13, 2q35, 10q22, 8q12, 1p32, 7p15, 15q21, have been described to be associated with 6p21.3 in reciprocal translocations.

no hybrid gene has been described yet; as for other mesenchymal tumors, the breakpoint is extragenic, located within a 80 kb region 3 of HMGIY

Hamartoma of the breast

benign tumor-like nodule of the breast, also called adenolipoma

good

one case with a t(1 ;6)(p21 ;21), involving the HMGIY gene has been described

Microfollicular adenoma of the thyroid

epithelial tumors

favorable

one case with a t(1;6)(p35;21) correlated with an overexpression of HMGIY has been described