Notice of Cyber Event

Updated February 6, 2026

Marin Cancer Care is providing notice of an event that may involve certain individuals’ information. Although we have no indication of identity theft or fraud in relation to this event, we are providing information about the event, the response, and additional measures individuals can take, should they feel it appropriate to do so. Marin Cancer Care’s investigation into this event is ongoing and this notice will be updated as additional relevant information is identified.

What Happened? On or about December 8, 2025, Marin Cancer Care learned that its computer network was accessed without permission and that certain files may have been copied and taken from the network. Upon discovery of this event, Marin Cancer Care began working with third party investigators to determine the full nature and scope of the event. The investigation identified signs of unauthorized access to Marin Cancer Care’s network between November 22, 2025 and December 6, 2025. As part of Marin Cancer Care’s ongoing investigation, it will be reviewing the files involved to identify the information contained within those files and to whom it may relate.

What Information Was Involved? Marin Cancer Care is conducting a full review of the files involved. This review is ongoing and Marin Cancer Care will provide further information once the review is completed. The information involved may include names, medical information, and health insurance information.

What We Are Doing. We are providing this notice and guidance about free resources that are available to assist with monitoring relevant accounts, credit reports, and how to place a fraud alert or security freeze on one’s credit file. Marin Cancer Care also took steps to secure its systems and is reviewing existing policies and procedures.

What Individuals Can Do. As a best practice, we encourage individuals to remain vigilant against incidents of identity theft and fraud by reviewing their account statements and monitoring their free credit reports for suspicious activity and to detect errors. Individuals can also review the below “Steps Individuals Can Take To Help Protect Personal Information”.

For More Information. If individuals have questions about this matter, please email us at privacy@marincancercare.com. This email is for the cyber event only. Please do not use this email to contact us about health concerns or medical problems. We do not monitor this email to answer medical questions. Individuals may also write to us at Marin Cancer Care, Attn: Compliance, 1350 South Eliseo Drive, Suite 200, Greenbrae, CA 94904.

Sincerely,

Marin Cancer Care

Steps Individuals Can Take To Help Protect Personal Information

Under U.S. law, a consumer is entitled to one free credit report annually from each of the three major credit reporting bureaus, Equifax, Experian, and TransUnion. To order a free credit report, visit www.annualcreditreport.com or call, toll-free, 1-877-322-8228. Consumers may also directly contact the three major credit reporting bureaus listed below to request a free copy of their credit report.

Consumers have the right to place an initial or extended “fraud alert” on a credit file at no cost. An initial fraud alert is a 1-year alert that is placed on a consumer’s credit file. Upon seeing a fraud alert display on a consumer’s credit file, a business is required to take steps to verify the consumer’s identity before extending new credit. If consumers are the victim of identity theft, they are entitled to an extended fraud alert, which is a fraud alert lasting seven years. Should consumers wish to place a fraud alert, please contact any of the three major credit reporting bureaus listed below.

As an alternative to a fraud alert, consumers have the right to place a “credit freeze” on a credit report, which will prohibit a credit bureau from releasing information in the credit report without the consumer’s express authorization. The credit freeze is designed to prevent credit, loans, and services from being approved in a consumer’s name without consent. However, consumers should be aware that using a credit freeze to take control over who gets access to the personal and financial information in their credit report may delay, interfere with, or prohibit the timely approval of any subsequent request or application they make regarding a new loan, credit, mortgage, or any other account involving the extension of credit. Pursuant to federal law, consumers cannot be charged to place or lift a credit freeze on their credit report. To request a credit freeze, individuals may need to provide some or all of the following information:

1. Full name (including middle initial as well as Jr., Sr., II, III, etc.);
2. Social Security number;
3. Date of birth;
4. Addresses for the prior two to five years;
5. Proof of current address, such as a current utility bill or telephone bill;
6. A legible photocopy of a government-issued identification card (state driver’s license or ID card, etc.); and
7. A copy of either the police report, investigative report, or complaint to a law enforcement agency concerning identity theft if they are a victim of identity theft.

Should consumers wish to place a credit freeze or fraud alert, please contact the three major credit reporting bureaus listed below:

Additional Information

Consumers may further educate themselves regarding identity theft, fraud alerts, credit freezes, and the steps they can take to protect their personal information by contacting the consumer reporting bureaus, the Federal Trade Commission, or their state attorney general. The Federal Trade Commission may be reached at: 600 Pennsylvania Ave NW, Washington, DC 20580; www.identitytheft.gov; 1-877-ID-THEFT (1-877-438-4338); and TTY: 1-866-653-4261. The Federal Trade Commission also encourages those who discover that their information has been misused to file a complaint with them. Consumers can obtain further information on how to file such a complaint by way of the contact information listed above. Consumers have the right to file a police report if they ever experience identity theft or fraud. Please note that in order to file a report with law enforcement for identity theft, consumers will likely need to provide some proof that they have been a victim. Instances of known or suspected identity theft should also be reported to law enforcement and the relevant state attorney general. This notice has not been delayed by law enforcement.