Melanoma Gene Expression Assay for Metastasis Risk Stratification

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Solution Overview

Problem

Current methods for predicting metastasis in cutaneous melanoma are inaccurate, leading to over-treatment or under-treatment of patients, and invasive biopsies like sentinel lymph node biopsies have low positivity rates and significant clinical complications.

Innovation Solution

A gene expression profile (GEP) assay measuring the levels of at least eight genes (BAP1_varA, BAP1_varB, MGP, SPP1, CXCL14, CLCA2, S100A8, BTG1, SAP130, ARG1, KRT6B, GJA, ID2, EIF1B, S100A9, CRABP2, KRT14, ROBO1, RBM23, TACSTD2, DSC1, SPRR1B, TRIM29, AQP3, TYRP1, PPL, LTA4H, and CST6) in primary cutaneous melanoma tumors using RT-PCR, followed by comparison to a predictive training set to classify metastatic risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sentinel lymph node biopsy is performed to detect metastasis, then metastasis detection capability is improved, but false negative rates remain high and clinical complications increase

Engineering Contradiction:
Improvemetastasis detection accuracyVSAvoidfalse negative rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical/invasive lymph node biopsy system with a molecular diagnostic system based on gene expression profiling. The GEP assay analyzes gene expression patterns in primary tumor tissue to predict metastatic risk, substituting the need for invasive lymph node sampling while improving detection accuracy and eliminating false negatives associated with histological analysis

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces gene expression profiles as an intermediary indicator to predict metastatic risk. Instead of directly examining lymph nodes, the system uses gene expression patterns in primary tumor tissue as a mediator to infer metastatic potential, thereby avoiding the limitations of direct lymph node biopsy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If current TNM staging system is used to guide treatment, then treatment decisions are made, but over-treatment and under-treatment occur due to poor prognostic accuracy

Engineering Contradiction:
Improvetreatment decision makingVSAvoidprognostic accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the parameters used for prognosis from anatomical/histological parameters (tumor size, lymph node involvement) to molecular parameters (gene expression levels). The GEP assay measures expression levels of multiple genes to generate a molecular signature that provides continuous, granular prognostic information, enabling more precise risk stratification and personalized treatment decisions

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If invasive biopsy methods are used to improve detection accuracy, then metastasis detection is enhanced, but patient exposure to clinical complications increases

Engineering Contradiction:
Improvemetastasis detection accuracyVSAvoidclinical complications
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the diagnostic information needed for metastasis prediction directly from primary tumor tissue through gene expression analysis, eliminating the need to extract and examine lymph node tissue. This extraction approach obtains the necessary diagnostic data without subjecting patients to invasive lymph node biopsy procedures and their associated complications

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The GEP assay provides a more accurate prediction of metastasis risk, with 5-year metastasis-free survival rates of 93-97% for low-risk tumors and 31-33% for high-risk tumors, improving prognostic accuracy and reducing unnecessary treatments.

Implementation Method 1

measuring gene-expression levels of at least eight genes... comprises measurement of a level of fluorescence by a sequence detection system following RT-PCR

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS20260015676A1Diagnostic test for predicting metastasis and recurrence in cutaneous melanoma
Publication Date: 2026.01.15 CASTLE BIOSCIENCES INC
  • US20260015676A1 patent drawing
  • US20260015676A1 patent drawing
  • US20260015676A1 patent drawing

AI summary

The invention as disclosed herein in encompasses a method for predicting the risk of metastasis of a primary cutaneous melanoma tumor, the method encompassing measuring the gene-expression levels of at least eight genes selected from a specific gene set in a sample taken from the primary cutaneous melanoma tumor; determining a gene-expression profile signature from the gene expression levels of the at least eight genes; comparing the gene-expression profile to the gene-expression profile of a predictive training set; and providing an indication as to whether the primary cutaneous melanoma tumor is a certain class of metastasis or treatment risk when the gene expression profile indicates that expression levels of at least eight genes are altered in a predictive manner as compared to the gene expression profile of the predictive training set.