Fifty-six women admitted consecutively for a breast biopsy were interviewed on the day prior to the operation. Interviewer ratings and blind ratings (audiotapes) allowed a [statistically significant (alpha = 5%)] differentiation of women in whom the biopsy revealed a cancer from those whose tumor was benign. The ratings took into account characteristics assumed to be typical of the women with cancer: (1) being inaccessible or overwhelmed when interviewed; (2) emotional suppression with sudden outbursts; (3) rationalization; (4) little or no anxiety before the operation; (5) demonstration of optimism; (6) superautonomous self-sufficiency; (7) altruistic behaviour; (8) harmonization and avoidance of conflicts. On the basis of the interviews the interviewer and a blind rater predicted the correct diagnosis in 83% and 94% of all cancer patients and in 71% and 68% of all benign cases. This result is also significant (alpha = 5%). The identified psychological syndrome was found in all breast cancer patients but also in a quarter to a third of the patients with benign nodes. We interpret it as a long-standing defensive pattern adopted in the face of extreme emotional stress. A possible etiological significance for the cancerous disease cannot be derived from this study.