Rearrangement of 9p13 as the primary chromosomal aberration in adenoid cystic carcinoma of the respiratory tract

Abstract

Two adenoid cystic carcinomas, one of the nasal cavity, the other a bronchial tumor, were cytogenetically analyzed. The former had a t(6;9)(q21-22;p 13-21) as the sole karyotypic abnormality. The latter had two related abnormal clones, resulting in the mosaic karyotype 46,XY,t(9;17)(p13;p13)/46,Y,t(X;6)(p22;q23),t(9;17)(p13;p13). The karyotypic profiles of the two cases, the only respiratory tract adenoid cystic carcinomas that have been cytogenetically characterized, differ little from those of previously reported adenoid cystic carcinomas of the major salivary glands, underscoring the fundamental biologic similarity among these tumors even when they develop from different structures and in different anatomical sites and organs. Because in the second case the t(9;17) obviously must have preceded the t(X;6), we conclude that both tumors had rearrangement of 9p13 as the primary cytogenetic change. The data thus add to the evidence that 6q changes are frequent, albeit at least sometimes secondary, aberrations in malignant salivary gland tumors. A subset of adenoid cystic carcinomas instead have rearrangement of 9p as the primary, and presumably pathogenetically essential, abnormality.

Salivary gland-type lung carcinomas: an EGFR immunohistochemical, molecular genetic, and mutational analysis study

“…38 A previous cytogenetic study on an adenoid cystic carcinoma of the respiratory tree did not reveal any alteration in the chromosome 7, instead translocations t(X;6) and t(9;17) were the main aberrations detected. 39 Therefore, our results support that polysomy of chromosome 7 is not uncommon in salivary gland-type carcinomas of the lung and had thus far not been well recognized.…”

Translocation t(6;14) as the Sole Chromosomal Abnormality in Adenoid Cystic Carcinoma of the Base of Tongue

“…In that context, balanced promiscuous translocations may lead to the formation of phenotypically similar tumors of different clinical outcomes and therapeutic sensitivities [30]. Since the translocations in our case and in all previously reported ACCs involving chromosome 6q were exclusively balanced in nature and limited to a few breakpoints and chromosomal partners, we contend that an activated oncogene or a fusion gene is likely underlying the development of at least a subset of ACC [3,4,7,8,11]. Recently, several candidate genes on the 6q21-25 regions have been investigated in ACCs but none was implicated in their development [18,21].…”

“…In addition, the 6q25 breakpoint in our case had also been found in two different cytogenetic analyses of ACCs [8,13] (Table 1). All together, 18 (48.6%) of the 37 ACCs cytogenetically analyzed to date manifested deletions and/or balanced translocations at the long arm of chromosome 6 [3][4][5][6][7][8][9][10][11][12]. Interestingly, the majority of these translocations involved the 6q regions in structural recombination with various chromosomal partners including 9q, 12q, 14q, 15q and Xp [23][24][25].…”

“…Attempts to understand the development and progression of these tumors have been unrewarding due to the lack of neoplastic precursors, difficulty in cultivating them and the absence of an animal model [1,2]. Identifying unique and consistent chromosomal abnormalities in this entity is necessary for the characterization of genetic events associated with its evolution and the development of novel biological targets for therapy [3][4][5][6][7][8][9][10][11][12].…”

Adenoid Cystic Carcinoma: Clinical and Molecular Features

“…Several cytogenetic studies of ACC described a reciprocal t(6;9) translocation occurring in some tumors [27][28][29][30]. However it was not clear initially if this was a common finding in ACC, and the described breakpoints of the t(6;9) translocations did not appear to be consistent enough to map specific gene loci.…”