Analysis of numerical chromosomal aberrations in adrenal cortical neoplasms by fluorescence in situ hybridization

We identified numerical chromosomal aberrations in adrenal cortical neoplasms using interphase fluorescence in situ hybridization (FISH) and correlated these aberrations with DNA ploidy and endocrine dysfunction.

Our study included 25 adenomas and 2 carcinomas associated with primary aldosteronism or Cushing's syndrome. Eight normal adrenal tissue samples served as controls. Isolated nuclei from frozen samples were used for FISH and formalin fixed, paraffin embedded tissues from the same materials were analyzed by flow cytometry for DNA ploidy. For FISH we used centromere specific probes for chromosomes 3, 7, 8, 11 and 12.

None of the normal adrenal tissues had any numerical chromosomal aberrations in any chromosome analyzed or any abnormal findings on DNA ploidy analysis. Tetrasomy of chromosomes 3, 7, 8, 11 and 12 was detected in 8, 13, 14, 11 and 12 of the 17 adenomas associated with primary aldosteronism, and in 2, 0, 0, 0 and 0 of the 8 associated with Cushing's syndrome, respectively. DNA flow cytometry revealed tetraploidy in 11 of the 17 cases of primary aldosteronism and in 1 of the 8 of Cushing's syndrome. Five diploid adenomas associated with primary aldosteronism also showed tetrasomy in 2 or more chromosomes. One of the 2 carcinomas showed aneuploidy and aneusomy of chromosomes 8, 11 and 12 but the other showed no abnormal peaks on DNA histography and no numerical chromosomal aberrations.

All chromosomes analyzed in adenomas associated with primary aldosteronism frequently showed tetrasomy, whereas few chromosomal abnormalities were detected in adenomas associated with Cushing's syndrome. Our results indicate that DNA tetraploidy is common in adrenal cortical adenomas associated with primary aldosteronism. Interphase FISH strongly supported flow cytometry findings and could provide further information on individual chromosomes.