Dr. Baselga stepped down in September from his role as chief medical officer at the cancer center after The New York Times and ProPublica reported that he had failed to accurately disclose his conflicts of interest in dozens of articles in medical journals. He later resigned from the boards of the drug maker Bristol-Myers Squibb and the radiation equipment manufacturer Varian Medical Systems.

Although Memorial Sloan Kettering has said that Dr. Baselga was not fired, hospital leaders have indicated that he was forced out. In October, Douglas A. Warner III, then the chairman of the cancer center’s board, told the staff that Dr. Baselga’s actions “left us no choice.”

In December, the American Association for Cancer Research said that Dr. Baselga, at its request, had resigned his post as one of two editors in chief of its medical journal Cancer Discovery because he did “not adhere to the high standards” of conflict-of-interest disclosures that the group expects of its leaders. Some of his omissions involved articles that were published in Cancer Discovery while he was an editor in chief.

A spokesman for AstraZeneca said Dr. Baselga was not available for comment, but the doctor told Reuters on Monday that he took responsibility for his disclosure lapses. He also said the cancer association had concluded his failures were “inadvertent,” and said many of his company relationships were publicly available on a federal database of physician payments by drug and device manufacturers. However, some of the relationships that Dr. Baselga failed to disclose were with small biotech start-ups that are not required to report to the federal government.

“Dr. Baselga is one of the best scientists in the field of oncology,” said the spokesman, Gonzalo Viña. “We evaluated the series of inadvertent omissions, which have since been addressed and it is not for us to comment about the previous roles he held.”