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Ace3Z/
graphist-v2

pytorch

graph-neural-networks

histopathology

self-supervised-learning

pytorch-geometric

graph-representation-learning

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GrapHist++: Edge-Informed Graph Self-Supervised Learning for Histopathology

Pre-trained weights, cell graphs and embeddings for the edge-informed extension of GrapHist. GrapHist encodes a slide as a sparse graph of cells and pre-trains an ACM-GIN encoder with masked feature reconstruction. GrapHist++ keeps that recipe and changes two things: each edge carries a 75-dimensional descriptor of the tissue between the two cells, and a VICReg variance/covariance term is added to the objective to stop the representation collapsing.

Original paper: arXiv:2603.00143 · model
Code: Ace3Z/GrapHist-V2
Data manual: DATA.md, mapping every artifact here to the result it reproduces

Results

Slide-level MIL, transfer to unseen cohorts (test macro-F1 %, best of three MIL heads):

	BRACS	BreakHis	BACH
GrapHist	60.30	89.37	69.16
GrapHist++	69.00	95.53	68.98

Survival on TCGA-BRCA (Cox PH, C-index): 0.793, against 0.763 for GrapHist, 0.724 MAE, 0.632 DINOv2. Cell-type identification (macro-F1 %): PanNuke 20× breast 58.57, 40× breast 58.38, NuCLS 7-class 27.09. The encoder is 7.98 M parameters, 9.29 M with the projection embed() runs through, inside a 10.53 M pre-training checkpoint; it embeds a patch in 0.093 ms at 0.327 GB peak memory (BACH, batch size 48, H200).

Without VICReg the encoder collapses (pca_1 ≈ 0.5, effective dimension ≈ 2 of 512); with it the same 100-epoch run finishes at 0.17 and 11.9. The term is training-only.

What's here

graphist_v2.pt      the released encoder (127 MB, md5 81a2e6b91cefff0bbbc13c6fd318ee78)
modeling/           build_model factory and the ACM-GINEConv backbone
graphs/             cell graphs: TCGA-BRCA, BACH, BRACS, BreakHis, SPIDER-breast
embeddings/         precomputed slide- and cell-level embeddings
baselines/          DINOv2, MAE and GrapHist v1 embeddings for comparison
labels/             slide labels and the TCGA-BRCA clinical export
studies/            homophily, AdapterGNN and preprocessing-runtime artifacts
upstream_v1/        the original GrapHist graphs, unchanged

The repository is ~1.05 TB, so fetch file by file rather than cloning it. DATA.md gives the per-cohort commands; the model alone is the six files in the snippet below.

Requirements

pip install torch torch-geometric huggingface_hub pandas numpy

pandas and numpy are needed only by modeling/graphist_utils.py, which holds the input transforms.

Graphs are PyTorch Geometric objects with x (n, 96), edge_index (2, e), edge_attr (e, 75) and batch. Column 0 of edge_attr is the centroid distance in µm and is used as the message weight, not as a feature.

Usage

python

import os, sys, torch
from huggingface_hub import hf_hub_download

# Fetch file by file. snapshot_download(allow_patterns=...) is equivalent on
# huggingface-hub >= 1.27, but silently skips LFS files on 1.7.1, which is the
# version the code repository pins, so it would return no checkpoint there.
for f in ["graphist_v2.pt", "modeling/graphist_utils.py",
          "modeling/models/__init__.py", "modeling/models/acm_gin.py",
          "modeling/models/acm_gineconv.py", "modeling/models/edcoder.py",
          "modeling/models/utils.py"]:
    hf_hub_download(repo_id="Ace3Z/graphist-v2", filename=f)

path = os.path.dirname(hf_hub_download(repo_id="Ace3Z/graphist-v2",
                                       filename="graphist_v2.pt"))
sys.path.insert(0, f"{path}/modeling")
from models import build_model

class Args:
    encoder = decoder = "acm_gineconv"
    num_features = 96                # per-cell features
    num_edge_features = 75           # projection sees 74; distance excluded
    num_hidden = 512
    num_layers = 5
    concat_hidden = True             # load-critical
    encoder_norm = "layer"           # load-critical
    edge_distance_in_proj = False    # load-critical
    input_norm = "none"
    batchnorm = False
    activation = "prelu"
    loss_fn = "sce"
    alpha_l = 3
    mask_rate = 0.5
    replace_rate = 0.1
    drop_edge_rate = 0.0
    vicreg_var_weight = 0.05         # training only
    vicreg_cov_weight = 0.002
    vicreg_gamma = 1.0

model = build_model(Args())
ckpt = torch.load(f"{path}/graphist_v2.pt", map_location="cpu", weights_only=False)
model.load_state_dict(ckpt["model_state_dict"], strict=True)
model.eval()

A graph has to go through the same three transforms the release was trained and evaluated with, or the embeddings will not match. They ship here, in modeling/graphist_utils.py:

python

import json
from torch_geometric.data import Batch
from torch_geometric.transforms import ToUndirected
from graphist_utils import NormalizeData, AddVirtualNode

scale_vals = json.load(open("normalization.json"))   # ships beside each cohort's graphs
graph = torch.load("some_graph.pt", weights_only=False)
for t in (ToUndirected(),
          NormalizeData(scale_vals, edge_attr_skip_cols=[0], min_std=0.01, clip=10),
          AddVirtualNode(mean_edge_distance=scale_vals["edge_attr"]["mean"][0])):
    graph = t(graph)

batch = Batch.from_data_list([graph])
with torch.no_grad():
    h = model.embed(batch.x, batch.edge_index, batch.edge_attr, batch.batch)

Skipping the transforms raises no error; it just yields different numbers. embed() returns one row per node including the synthetic virtual node, so a 16-cell graph gives (17, 512); drop the last row before pooling to a patch vector.

Three arguments decide whether the weights load at all. encoder_norm must be "layer" and edge_distance_in_proj must be False (both defaults are wrong for this checkpoint), and concat_hidden must be True, which has no default. Anything else raises a shape or key error.

Licence and citation

Released under the MIT licence, matching the code repository.

That covers what this repository adds. It cannot relicense the source data, and three upstream terms travel with the derivatives:

What	Upstream terms
`upstream_v1/`, `studies/adaptergnn/graphs_v1/`	`cc-by-nc-sa-4.0` from the GrapHist v1 datasets: non-commercial and share-alike
`graphs/spider_breast/`	`cc-by-nc-4.0`, research use only
`baselines/graphist_v1/graphist_v1.pt`	`apache-2.0`, byte-identical to the released GrapHist v1 checkpoint

labels/tcga_brca_clinical.tsv is the open-access GDC clinical export, redistributed under TCGA's open-access terms. The source cohorts keep their own licences, so cite their papers alongside GrapHist.

The architecture adapts GraphMAE and ACM-GNN; the regularizer follows VICReg.

bibtex

@misc{ogut2026graphist,
    title  = {GrapHist: Graph Self-Supervised Learning for Histopathology},
    author = {Sevda {\"O}{\u{g}}{\"u}t and C{\'e}dric Vincent-Cuaz and Natalia Dubljevic and
              Carlos Hurtado and Vaishnavi Subramanian and Pascal Frossard and Dorina Thanou},
    year   = {2026},
    eprint = {2603.00143},
    url    = {https://arxiv.org/abs/2603.00143},
}