ONCOSEM ONKOLOJİK SİSTEMLER SANAYİ VE TİCARET A.Ş. (Sorumluluk Beyanı (Konsolide))

With respect to the consolidated statement of financial position, statement of comprehensive income, statement of cash flows and statement of changes in equity, together with the accompanying notes, and the Activity Report of our Company for the period from 01 January 2026 to 30 September 2026, prepared in accordance with the Turkish Accounting Standards/Turkish Financial Reporting Standards ("TAS/TFRS") and the formats prescribed by the Capital Markets Board of Türkiye ("CMB"), pursuant to the CMB Communiqué No. II-14.1 on the "Principles of Financial Reporting in Capital Markets" (the "Communiqué"), and in accordance with the CMB regulations, we hereby declare that:

·         We have reviewed the aforementioned financial statements and the Activity Report.

·         To the best of our knowledge and within the scope of our duties and responsibilities in our Company, the financial statements and the Activity Report do not contain any untrue statement on material matters or any omissions that may result in the disclosures being misleading as of the date on which they were made.

·         To the best of our knowledge and within the scope of our duties and responsibilities in our Company, the financial statements prepared in accordance with the Communiqué, including those within the scope of consolidation, fairly and accurately reflect the assets, liabilities, financial position, and profit or loss of our Company; and the Activity Report fairly reflects the development and performance of the business, as well as the financial position of our Company, including those within the scope of consolidation, together with the significant risks and uncertainties faced.

We hereby submit the foregoing for your information and declare that we are responsible for the disclosures made.

Yours sincerely,

Oncosem Onkolojik Sistemler Sanayi ve Ticaret A.Ş.

The English translation of this disclosure is attached hereto. In case of any discrepancy between the Turkish and English versions of the disclosure, the Turkish version shall prevail.