Layers learn from features to higher-level concepts.
Clinical Use Case
Biomarker Classification
🧬 The Task
Building a model to predict drug response based on a specific gene signature or protein profile.
🛠 Tools
Google Teachable Machine: Fast, no-code vision/audio/pose models.
Scikit-learn (via Agents): Random Forests and SVMs for tabular omics data.
# Teachable Machine Workflow
1. Collect samples (e.g., Histology slides: Normal vs. Malignant).
2. Train in browser.
3. Export model for use in clinical decision support apps.
Validation
Evaluation: Beyond Accuracy
Accuracy is misleading in biomedical data where one class (e.g., rare disease) is infrequent.
Precision: "Of all predicted positive, how many were actually positive?"
Recall (Sensitivity): "Of all actual positive, how many did we find?"
AUC-ROC: Overall ability of the model to distinguish between classes.
📊 The Bio-Tradeoff
In cancer screening, we prioritize **Recall** (don't miss any disease) even if **Precision** suffers (more false positives for review).
Pitfalls
The Overfitting Trap
⚠️ Small Data, Big Models
Biomedical datasets often have few samples (n < 100) but many features (p > 20,000 genes). This is a recipe for overfitting.
Solutions
Cross-Validation: Testing on multiple "folds" of data.