HEMnet - Haematoxylin & Eosin and Molecular neural network

Overview

HEMnet predicts regions of cancer cells from standard Haematoxylin and Eosin (H&E) stained tumour tissue sections. It leverages molecular labelling - rather than time-consuming and variable pathologist annotations - to annotate H&E images used to train a neural network to predict cancer cells from H&E images alone. We trained HEMnet to predict colon cancer (try it out in our Colab notebook), however, you can train HEMnet to predict other cancers where you have molecular staining for a cancer marker available.

Getting Started

The easiest way to apply HEMnet is to use predict H&E images with our pretrained model for colorectal cancer using our google colab notebook. By default it downloads a slide from TCGA, however, you can also upload your own slide(s) in an .svs format.

To train new models with HEMnet or predict on H&E images on your own machine, we recommend installing the HEMnet environment.

Installation

We recommend running HEMnet from our docker image for the simplest and most reliable setup. Alternatively, if you wish to setup a conda environment, we provide an environment.yml file.

1. Docker

You can download the docker image and run the docker container using the following commands:

```
docker pull andrewsu1/hemnet docker run -it andrewsu1/hemnet
```

The docker image contains a conda environment from which you can run HEMnet.

2. Conda

Install Openslide (this is necessary to open whole slide images) - download it here

Create a conda environment from the environment.yml file

conda env create -f environment.yml
conda activate HEMnet

Usage

Slide Preparation

Name slides in the format: slide_id_TP53 for TP53 slides and slide_id_HandE for H&E slides The TP53 and HandE suffix is used by HEMnet to identify the stain used.

1. Generate training and testing datasets

a. Generate train dataset

python HEMnet_train_dataset.py -b /path/to/base/directory -s relative/path/to/slides -o relative/path/to/output/directory -t relative/path/to/template_slide.svs -v

b. Generate test dataset

python HEMnet_test_dataset.py -b /path/to/base/directory -s /relative/path/to/slides -o /relative/path/to/output/directory -t relative/path/to/template_slide -m tile_mag -a align_mag -c cancer_thresh -n non_cancer_thresh

Other parameters:

• -t is the relative path to the template slide from which all other slides will be normalised against. The template slide should be the same for each step.
• -m is the tile magnification. e.g. if the input is 10 then the tiles will be output at 10x
• -a is the align magnification. Paired TP53 and H&E slides will be registered at this magnification. To reduce computation time we recommend this be less than the tile magnification - a five times downscale generally works well.
• -c cancer threshold to apply to the DAB channel. DAB intensities less than this threshold indicate cancer.
• -n non-cancer threshold to apply to the DAB channel. DAB intensities greater than this threshold indicate no cancer.

2. Train and evaluate model

a. Training model

python train.py -b /path/to/base/directory -t relative/path/to/training_tile_directory -l relative/path/to/validation_tile_directory -o /relative/path/to/output/directory -m cnn_base -g num_gpus -e epochs -a batch_size -s -w -f -v

Other parameters:

• -m is CNN base model. eg. resnet50, vgg16, vgg19, inception_v3 and xception.
• -g is number of GPUs for training.
• -e is training epochs. Default is 100 epochs.
• -a is batch size. Default is 32
• -s is option to save the trained model weights.
• -w is option to used transfer learning. Model will used pre-trained weights from ImageNet at the initial stage.
• -f is fine-tuning option. Model will re-train CNN base.

b. Test model prediction

python test.py -b /path/to/base/directory -t relative/path/to/test_tile_directory -o /relative/path/to/output/directory -w model_weights -m cnn_base -g num_gpus -v

Other parameters:

• -w is path to trained model. eg. trained_model.h5.
• -m is CNN base model (same to training step).
• -g is number of GPUs for prediction.

c. Evaluate model performance and visualise model prediction

python visualisation.py -b /path/to/base/directory -t /relative/path/to/training_output_directory -p /relative/path/to/test_output_directory -o /relative/path/to/output/directory -i sample

Other parameters:

• -t is path to training outputs.
• -p is path to test outputs.
• -i is name of Whole Slide Image for visualisation.

3. Apply model to diagnose new images

python HEMnet_inference.py -s '/path/to/new/HE/Slides/' -o '/path/to/output/directory/' -t '/path/to/template/slide/' -nn '/path/to/trained/model/' -v

Data Availability

Images used for training HEMnet can be downloaded from: https://dna-discovery.stanford.edu/publicmaterial/web-resources/HEMnet/images/

Citing HEMnet

Su, A., Lee, H., Tan, X. et al. A deep learning model for molecular label transfer that enables cancer cell identification from histopathology images. npj Precis. Onc. 6, 14 (2022). https://doi.org/10.1038/s41698-022-00252-0

The Team

Please contact Dr Quan Nguyen (quan.nguyen@uq.edu.au), Dr. HoJoon Lee (hojoon@stanford.edu), Andrew Su (a.su@uqconnect.edu.au), and Xiao Tan (xiao.tan@uqconnect.edu.au) for issues, suggestions, and we are very welcome to collaboration opportunities.