From the Guidelines
High-grade serous carcinoma is indeed considered a type of epithelioid carcinoma, as it is a malignant epithelial tumor that originates in the ovaries, fallopian tubes, or peritoneum and maintains epithelial-like characteristics. According to the most recent and highest quality study, 1, high-grade serous carcinoma (HGSC) is the most common and most lethal type of tubo-ovarian carcinoma, accounting for approximately 70% of cases. The 2020 World Health Organization (WHO) classification recognizes HGSC as a distinct subtype of malignant epithelial ovarian cancer, with specific molecular and histological features that distinguish it from other types of epithelial cancers 1.
Key Characteristics of High-Grade Serous Carcinoma
- High-grade serous carcinoma is characterized by the presence of epithelial cells that form glandular structures and papillary projections
- It is a malignant epithelial tumor that typically originates in the ovaries, fallopian tubes, or peritoneum
- The term "epithelioid" refers to cells that resemble epithelial cells in their shape and arrangement
- In high-grade serous carcinoma, the cancer cells are derived from epithelial tissue and maintain epithelial-like characteristics
Importance of Classification
The classification of high-grade serous carcinoma as an epithelioid carcinoma is important for understanding the tumor's behavior, treatment approaches, and prognosis. As noted in 1, accurate typing of ovarian carcinoma will become increasingly important with the introduction of targeted therapies and specific treatments for different tumor types. Furthermore, the recognition of distinct molecular and histological features of HGSC can inform treatment decisions and improve patient outcomes 1.
Molecular and Histological Features
High-grade serous carcinoma has specific molecular and histological features that distinguish it from other types of epithelial cancers. For example, HGSC is often associated with BRCA1/2 mutations and homologous recombination deficiency (HRD), which can inform treatment decisions and predict response to targeted therapies such as poly (ADP-ribose) polymerase inhibitors (PARPis) 1. Additionally, the genomic and transcriptional features of HGSC are similar to those of basal-like breast cancers, highlighting the importance of considering the molecular characteristics of the tumor in treatment decisions 1.
From the Research
Definition and Classification of High-Grade Serous Carcinoma
- High-grade serous carcinoma (HGSOC) is a subtype of epithelial ovarian cancer, which is the most aggressive form of ovarian cancer 2, 3.
- HGSOC is characterized by nearly universal mutation in and dysfunction of p53, genomic instability, and advanced stage at onset 3.
- It is considered a unique type of epithelial cancer, with probable fallopian tube epithelium origin, and a serous tubal in situ carcinoma precursor 3.
Relationship between High-Grade Serous Carcinoma and Epithelioid Carcinoma
- Epithelioid carcinoma is not explicitly defined in the provided studies, but HGSOC is classified as a type of epithelial ovarian cancer 2, 3, 4, 5, 6.
- The studies suggest that HGSOC is a distinct entity within the category of epithelial ovarian cancers, with its own set of molecular and morphological characteristics 2, 3, 6.
- While the term "epithelioid" is not used to describe HGSOC in the provided studies, it can be inferred that HGSOC is a type of carcinoma that arises from epithelial cells, given its classification as an epithelial ovarian cancer 2, 3, 4, 5, 6.
Molecular Characteristics of High-Grade Serous Carcinoma
- HGSOC is characterized by mutations in genes such as TP53, BRCA1, and BRCA2, which are involved in DNA repair and genomic stability 2, 3.
- The disease is also associated with homologous recombination dysfunction (HRD), which can be detected using molecular biomarkers 3, 4.
- Molecular subtypes of HGSOC have been identified, including C1 (mesenchymal), C2 (immunoreactive), C4 (differentiated), and C5 (proliferative), which correlate with patient survival and have distinct biological features 6.