Department of Pathology, University of Campinas/UNICAMP, Brazil.
Cell Oncol (Dordr). 2011 Aug;34(4):369-79. doi: 10.1007/s13402-011-0037-5. Epub 2011 May 4.
ACC can occasionally undergo dedifferentiation also referred to as high-grade transformation (ACC-HGT). However, ACC-HGT can also undergo transformation to adenocarcinomas which are not poorly differentiated. ACC-HGT is generally considered to be an aggressive variant of ACC, even more than solid ACC. This study was aimed to describe the genetic changes of ACC-HGT in relation to clinico-pathological features, and to compare results to solid ACC.
Genome wide DNA copy number changes were analyzed by microarray CGH in ACC-HGT, four with transformation into moderately differentiated adenocarcinoma (MDA) and two into poorly differentiated carcinoma (PDC), and five solid ACC. In addition, Ki67 index and p53 immunopositivity was assessed.
ACC-HGT carried fewer copy number changes compared to solid ACC. Two ACC-HGT cases harboured a breakpoint at 6q23, near the cMYB oncogene. The complexity of the genomic profile concurred with the clinical course of the patient. Among the ACC-HGT, p53 positivity significantly increased from the conventional to the transformed (both MDA and PDC) component.
ACC-HGT may not necessarily reflect a more advanced stage of tumor progression, but rather a transformation to another histological form in which the poorly differentiated forms (PDC) presents a genetic complexity similar to the solid ACC.
ACC 偶尔会发生去分化，也称为高级别转化（ACC-HGT）。然而，ACC-HGT 也可能转化为非低分化的腺癌。ACC-HGT 通常被认为是 ACC 的侵袭性变异型，甚至比实体型 ACC 更具侵袭性。本研究旨在描述 ACC-HGT 的遗传变化与临床病理特征的关系，并将结果与实体型 ACC 进行比较。
通过微阵列 CGH 分析 ACC-HGT、4 例转化为中度分化腺癌（MDA）和 2 例转化为低分化癌（PDC）以及 5 例实体型 ACC 的全基因组 DNA 拷贝数变化。此外，评估了 Ki67 指数和 p53 免疫阳性率。
与实体型 ACC 相比，ACC-HGT 的拷贝数变化较少。2 例 ACC-HGT 病例在 6q23 附近存在断点，靠近 cMYB 癌基因。基因组图谱的复杂性与患者的临床病程相符。在 ACC-HGT 中，p53 阳性率从常规成分到转化成分（MDA 和 PDC）显著增加。
ACC-HGT 不一定反映肿瘤进展的更晚期阶段，而是向另一种组织学形式的转化，其中低分化形式（PDC）具有与实体型 ACC 相似的遗传复杂性。
