Amplification of oncogenes erbB-2, erbB-1, and c-myc and loss of heterozygosis (LH) in chromosome 11p (probe hras-1), 17p (probe ynz-22), and 17q (probe thh-59) were studied in 165 malignant tumors (60 breast, 22 ovary, 40 colorectal, 23 lung, and 20 thyroid carcinomas). A correlation (P < 0.01) was found between amplification of these oncogenes and 17p deletions: increased copy number was observed in 11 of 46 tumors with LH but in only 3 of 61 with preserved heterozygosis in probe ynz-22. This correlation was mainly due to a high incidence of erbB-2 amplification combined with 17p deletion, whereas the incidence of extra copies of erbB-1 and c-myc was too low for any certain conclusions about the association of their alteration with LH in chromosome 17.