This paper extends the functional law of Autological Recursion (Ψ = ∂S/∂R) into biological systems, proposing a structural model of cancer as a breakdown of recursive self-modification. In this view, malignancy arises not from uncontrolled growth alone but from a loss of reflexivity—cells that can no longer update the regulatory rules governing their own behaviour (Ψ ≈ 0). The paper introduces measurable proxies (Ψ_eff, L_eff, C) derived from single-cell RNA and ATAC data to quantify structural sensitivity, energetic efficiency, and identity coherence. A digital tumour twin framework is outlined to simulate rule-based evolution and predict adaptive recovery trajectories under controlled perturbation. Instead of framing oncology as a mutation cascade, the model interprets it as a syntax failure of life’s recursive grammar—where evolution stops learning. The study proposes an ethical, ex vivo experimental roadmap using reversible CRISPRi/a editing under strict autological governance, emphasising reversibility, transparency, and safety. KOGNETIK Research Series Paper 004 — Autological Oncology (2025)A functional model of structural evolution in cellular systems. Note: This work is exploratory and aims to provide a functional language for self-modification across biological and cognitive systems. It is not intended as medical advice or therapeutic claim, but as a structural hypothesis for empirical testing. Intellectual Property & ContactKOGNETIK® is a registered trademark of Serkan Elbasan (Germany).The KOGNETIK Research Series is released under the Creative Commons Attribution 4.0 International License (CC BY 4.0). All scientific works within the series are open for citation and derivative research under proper attribution.For partnerships, translations, or applied development inquiries:✉️ research@kognetik.de · 🌐 https://www.kognetik.de https://orcid.org/0009-0000-8544-4847 Kognetik Series Information KOGNETIK — Minimal Operator Definition of Reflexivity (Ψ = ∂S/∂R) Reflexivity as structural rate-of-change:Ψ=∂S/∂R measures structural drift under recurrence. Process, not state:Reflexivity is a transformation rule, not a content or level. Domain-independent operator:Valid across biological, cognitive, artificial, social, industrial, and geophysical systems. Non-ascriptive, empirically testable:Ψ compares systems by observable structure and recurrence. Higher-order phenomena as specifications:Learning, adaptation, consciousness, governance, and identity are structured regimes of Ψ.