DeepProfile: A New Approach to Cancer Gene Analysis
DeepProfile enhances understanding of gene expression in various cancers to inform treatment strategies.
Su-In Lee, W. Qiu, A. B. Dincer, J. Janizek, S. Celik, M. Pittet, K. Naxerova
― 7 min read
Table of Contents
Gene expression is how cells use genes to make proteins and perform their functions. It reflects complex activities inside cells. Researchers want to study how genes are expressed in different types of cancer to gain insights into the causes and possible treatments. One useful way to analyze gene expression data is through a method called Unsupervised Learning. This method helps identify patterns in data without prior labels or classifications.
Unsupervised learning reduces the complexity of data and reveals underlying factors that explain variations in gene expression. This can help identify important characteristics of different cancers and their responses to treatments. However, many traditional methods of unsupervised learning can only find simple relationships. Recent advancements in artificial intelligence, particularly Deep Learning, show promise in capturing more complex patterns in gene expression.
The Challenges
While deep learning can analyze gene expression data effectively, there are some challenges to overcome. One issue is that deep learning models can become too focused on specific patterns if not enough data is available, a problem known as overfitting. The learning process itself can produce different results each time due to its random nature, making it hard to achieve consistent findings.
Additionally, the inner workings of deep learning models can be difficult to understand, leading to confusion about how the results relate to the biology of cancer. This lack of transparency can hinder the interpretation of findings, which is critical in biological research.
The Approach
To tackle these challenges, a new framework called DeepProfile was developed. This framework combines deep learning with robust data collection methods to analyze gene expression data across multiple types of cancers. The framework gathers gene expression data from public databases, allowing researchers to build a comprehensive picture of gene activity across 18 different cancer types.
DeepProfile uses a technique called Variational Autoencoders (VAEs). VAEs help compress high-dimensional gene expression data into a simpler form while preserving essential information. By combining results from different models trained with various configurations, DeepProfile helps increase the reliability of the findings.
Data Collection
The first step in using DeepProfile is collecting gene expression data from various sources. Researchers gathered data from public gene expression repositories for 18 different types of cancer. This data set contained information from over 50,000 samples, providing a broad range of expression profiles. The collected data was preprocessed to ensure consistency and usability.
Learning the Patterns
Once the data is ready, it is analyzed using the DeepProfile framework. The core of this analysis involves training the VAE models, which compress the data and reveal latent variables. This means identifying key factors that explain the variations in gene expression across cancer types.
After running the models, DeepProfile generates embeddings that represent each cancer type. These embeddings help researchers visualize and understand how Gene Expressions relate to each type of cancer. Each latent variable corresponds to specific characteristics of cancer samples, allowing for an in-depth comparison across cancer types.
Interpreting Results
DeepProfile doesn’t just analyze the data; it also interprets the results to identify which genes and pathways are most significant. It assigns attribution scores to genes linked to each latent variable, helping to highlight their importance in cancer biology. This part of the analysis is crucial because it reveals which genes contribute significantly to the overall expression variation.
Researchers can then run Pathway Enrichment tests to identify biological pathways associated with these important genes. Pathways are groups of related genes that work together to carry out a specific function in the body. By understanding which pathways are involved in various cancers, researchers can gain insights into cancer behavior and treatment options.
Pan-Cancer Analysis
One of the standout features of DeepProfile is its ability to perform pan-cancer analysis. This means it can look across multiple cancer types to identify common patterns and differences in gene expression. The analysis not only evaluates how similar or different cancer types are, but it also attempts to determine how well the embeddings preserve crucial biological signals.
Using DeepProfile, researchers can assess survival rates of cancer patients based on gene expression profiles, identify shared patterns among different cancers, and differentiate characteristics unique to specific cancer types.
Key Findings
Analysis through DeepProfile reveals important genes and pathways that control various aspects of cancer biology. For instance, the analysis identifies universally significant genes that play a major role in regulating immune responses. It becomes clear that certain genes influence how immune cells interact with tumors, which can affect tumor behavior and patient outcomes.
DeepProfile also highlights cancer-type specific genes that are crucial for defining distinct cancer subtypes. These findings show how different tumors might respond differently to treatments based on their specific gene expression patterns.
Immune Response Insights
One notable observation from the analysis is that specific immune-related genes are consistently important across many cancer types. These genes may not just be markers of immune cell presence; they could also indicate how tumors modulate their immune environment to promote growth. This is vital information for developing immune-based therapies in cancer treatment.
The pathways associated with immune responses also stand out. For example, pathways related to antigen presentation are significantly associated with patient survival across various cancers. Understanding these pathways helps researchers uncover how immune responses contribute to cancer progression and patient outcomes.
Cancer-Specific Pathways
DeepProfile’s extensive analysis also identifies unique pathways associated with specific cancer types. For example, certain pathways related to metabolic processes are highlighted for specific cancers, such as leukemia or brain tumors. This suggests that the metabolic needs and behaviors of different cancer types can affect their biology and treatment responses.
By analyzing these cancer-type specific pathways, researchers can gain insights into potential vulnerabilities in certain tumors that may be targeted with therapies. This level of detail helps improve personalized medicine approaches, ensuring that patients receive the most appropriate treatments for their specific cancer type.
Linking with Clinical Outcomes
A significant contribution of DeepProfile is its ability to connect gene expression data with clinical outcomes, such as patient survival. Through careful analysis, researchers can identify pathways associated with better or worse outcomes for patients. These insights can inform treatment strategies and improve patient prognoses.
For instance, the analysis found that a particular pathway related to DNA damage repair was linked to improved survival rates in patients with certain cancers. This information can help guide decisions about treatment options, such as whether a patient might benefit from therapies targeting DNA repair mechanisms.
Conclusion
DeepProfile represents a major advancement in analyzing gene expression data from cancer samples. By combining deep learning with robust data collection and interpretation methods, it offers a powerful tool for understanding cancer biology. The framework allows researchers to identify significant genes, pathways, and patterns that contribute to cancer development and treatment response.
Through extensive analysis, DeepProfile has revealed valuable insights into both common and unique aspects of cancer biology across different tumor types. This information can aid in the development of new therapies and improve patient outcomes by tailoring treatments to the specific characteristics of each cancer.
DeepProfile thus serves as a vital resource for researchers aiming to uncover the complexities of cancer and explore innovative approaches to treatment. Its ability to bridge the gap between data and biological insights marks a significant step forward in cancer research and personalized medicine.
Title: A deep profile of gene expression across 18 human cancers
Abstract: Clinically and biologically valuable information may reside untapped in large cancer gene expression data sets. Deep unsupervised learning has the potential to extract this information with unprecedented efficacy but has thus far been hampered by a lack of biological interpretability and robustness. Here, we present DeepProfile, a comprehensive framework that addresses current challenges in applying unsupervised deep learning to gene expression profiles. We use DeepProfile to learn low-dimensional latent spaces for 18 human cancers from 50,211 transcriptomes. DeepProfile outperforms existing dimensionality reduction methods with respect to biological interpretability. Using DeepProfile interpretability methods, we show that genes that are universally important in defining the latent spaces across all cancer types control immune cell activation, while cancer type-specific genes and pathways define molecular disease subtypes. By linking DeepProfile latent variables to secondary tumor characteristics, we discover that tumor mutation burden is closely associated with the expression of cell cycle-related genes. DNA mismatch repair and MHC class II antigen presentation pathway expression, on the other hand, are consistently associated with patient survival. We validate these results through Kaplan-Meier analyses and nominate tumor-associated macrophages as an important source of survival-correlated MHC class II transcripts. Our results illustrate the power of unsupervised deep learning for discovery of cancer biology from existing gene expression data.
Authors: Su-In Lee, W. Qiu, A. B. Dincer, J. Janizek, S. Celik, M. Pittet, K. Naxerova
Last Update: 2024-10-26 00:00:00
Language: English
Source URL: https://www.biorxiv.org/content/10.1101/2024.03.17.585426
Source PDF: https://www.biorxiv.org/content/10.1101/2024.03.17.585426.full.pdf
Licence: https://creativecommons.org/licenses/by-nc/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
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