depmap

Files (2)

• SKILL.md
• dependency_analysis.md · references/

SKILL.md (first lines)

# DepMap — Cancer Dependency Map

## Overview

The Cancer Dependency Map (DepMap) project, run by the Broad Institute, systematically characterizes genetic dependencies across hundreds of cancer cell lines using genome-wide CRISPR knockout screens (DepMap CRISPR), RNA interference (RNAi), and compound sensitivity assays (PRISM). DepMap data is essential for:
- Identifying which genes are essential for specific cancer types
- Finding cancer-selective dependencies (therapeutic targets)
- Validating oncology drug targets
- Discovering synthetic lethal interactions

**Key resources:**
- DepMap Portal: https://depmap.org/portal/
- DepMap data downloads: https://depmap.org/portal/download/all/
- Python package: `depmap` (or access via API/downloads)
- API: https://depmap.org/portal/api/

## When to Use This Skill

Use DepMap when:

- **Target validation**: Is a gene essential for survival in cancer cell lines with a specific mutation (e.g., KRAS-mutant)?
- **Biomarker discovery**: What genomic features predict sensitivity to knockout of a gene?
- **Synthetic lethality**: Find genes that are selectively essential when another gene is mutated/deleted
- **Drug sensitivity**: What cell line features predict response to a compound?
- **Pan-cancer essentiality**: Is a gene broadly essential across all cancer types (bad target) or selectively essential?
- **Correlation analysis**: Which pairs of genes have correlated dependency profiles (co-essentiality)?

## Core Concepts

### Dependency Scores

| Score | Range | Meaning |
|-------|-------|---------|
| **Chronos** (CRISPR) | ~ -3 to 0+ | More negative = more essential. Common essential threshold: −1. Pan-essential genes ~−1 to −2 |
| **RNAi DEMETER2** | ~ -3 to 0+ | Similar scale to Chronos |
| **Gene Effect** | normalized | Normalized Chronos; −1 = median effect of common essential genes |

**Key thresholds:**
- Chronos ≤ −0.5: likely dependent
- Chronos ≤ −1: strongly dependent (common essential range)

### Cell Line Annotations

Each cell line has:
- `DepMap_ID`: unique identifier (e.g., `ACH-000001`)
- `cell_line_name`: human-readable name
- `primary_disease`: cancer type
- `lineage`: broad tissue lineage
- `lineage_subtype`: specific subtype

## Core Capabilities

### 1. DepMap API

```python
import requests
import pandas as pd

BASE_URL = "https://depmap.org/portal/api"

def depmap_get(endpoint, params=None):
    url = f"{BASE_URL}/{endpoint}"
    response = requests.get(url, params=params)
    response.raise_for_status()
    return response.json()
```

### 2. Gene Dependency Scores

```python
def get_gene_dependency(gene_symbol, dataset="Chronos_Combined"):
    """Get CRISPR dependency scores for a gene across all cell lines."""
    url = f"{BASE_URL}/gene"
    params = {
        "gene_id": gene_symbol,
        "dataset": dataset
    }
    response = requests.get(url, params=params)
    return response.json()

# Alternatively, use the /data endpoint:
def get_dependencies_slice(gene_symbol, dataset_name="CRISPRGeneEffect"):
    """Get a gene's dependency slice from a dataset."""
    url = f"{BASE_URL}/data/gene_dependency"
    params = {"gene_name": gene_symbol, "dataset_name": dataset_name}
    response = requests.get(url, params=params)
    data = response.json()
    return data
```

### 3. Download-Based Analysis (Recommended for Large Queries)

For large-scale analysis, download DepMap data files and analyze locally:

```python
import pandas as pd
import requests, os

def download_depmap_data(url, output_path):
    """Download a DepMap data file."""
    response = requests.get(url, stream=True)
    with open(output_path, 'wb') as f:
        for chunk in response.iter_content(chunk_size=8192):
            f.write(chunk)

# DepMap 24Q4 data files (update version as needed)
FILES = {
    "crispr_gene_effect": "https://figshare.com/ndownloader/files/...",
    # OR download from: https://depmap.org/portal/download/all/
    # Files available:
    # CRISPRGeneEffect.csv - Chronos gene effect scores
    # OmicsExpressionProteinCodingGenesTPMLogp1.csv - mRNA expression
    # OmicsSomaticMutationsMatrixDamaging.csv - mutation binary matrix
    # OmicsCNGene.csv - copy number
    # sample_info.csv - cell line metadata
}

def load_depmap_gene_effect(filepath="CRISPRGeneEffect.csv"):
    """

From LUNARTECH-X/superpowers, CC-BY-4.0.

More from LUNARTECH-X/superpowers