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Molecular and clinicopathological characterization of luminal HER2-enriched breast cancer

Hohmann, Lennart (2022) BINP52 20212
Degree Projects in Bioinformatics
Popular Abstract
What is luminal HER2-enriched breast cancer?

Breast cancer is the most common cancer amongst women worldwide. While many people think of breast cancer as a singular disease it actually represents an umbrella term covering numerous different types of tumors that are characterized by specific molecular profiles and morphologies, bearing distinct clinical implications. In this light, the adequate subtyping and characterization of breast cancer to make well considered treatment decisions is of outmost importance.

Clinically, breast cancer is divided into three main subgroups based on the assessment of the abundance of two hormone receptors (the estrogen receptor alpha (ER) and the progesterone receptor (PR)) and a protein called the... (More)
What is luminal HER2-enriched breast cancer?

Breast cancer is the most common cancer amongst women worldwide. While many people think of breast cancer as a singular disease it actually represents an umbrella term covering numerous different types of tumors that are characterized by specific molecular profiles and morphologies, bearing distinct clinical implications. In this light, the adequate subtyping and characterization of breast cancer to make well considered treatment decisions is of outmost importance.

Clinically, breast cancer is divided into three main subgroups based on the assessment of the abundance of two hormone receptors (the estrogen receptor alpha (ER) and the progesterone receptor (PR)) and a protein called the human epidermal growth factor receptor 2 (HER2) on the surface of cancer cells. Based on these assessments, the tumors that are identified to have high levels of ER and low levels of HER2 are marked as being HER2-/ER+ (also known as “luminal breast cancer”), which is an important factor in the clinician’s choice of treatment for affected patients. In recent years a different approach to breast cancer subtyping has found its way into clinical practice and is now used to refine treatment decisions. By assessing the activity of a set of 50 genes within luminal breast cancer, new subtypes are classified that improve the representation of the subgroup’s inherent clinical and biological heterogeneity. One of these subtypes is HER2-enriched (HER2E), which despite being associated with a poor prognosis holds no implications for clinical treatment decisions because of a lack of insight into its characterizing molecular features. Therefore, the study at hand aimed to comprehensively characterize luminal HER2E breast cancer to evaluate the response of patients to conventionally administered therapies and identify molecular features that might be used to inform treatment decisions in the future.

To that end breast cancer datasets of two large independent studies were used to perform bioinformatic analyses looking into clinicopathological and molecular features within the luminal HER2E subtype.

The results demonstrated that patients with luminal HER2E tumors comprise a small but clinically important subgroup that suffers from a fast disease recurrence, regardless of current standard of care treatment. Molecular features indicate that these tumors grow very fast and have a low activity of the ER-associated gene ESR1, which might explain why some standard therapy options do not work. Additionally, HER2E tumors were found to be associated with a high immune response, a high burden of changes in the genomic structure and frequent mutations in the tumor suppressing gene TP53.

Master’s Degree Project in Bioinformatics 60 credits 2022
Department of Biology, Lund University
Advisor: Johan Staaf, Phd
Breast and Lung Cancer Research Group, Division of Oncology, Department of Clinical Sciences Lund, Lund University, Sweden (Less)
Please use this url to cite or link to this publication:
author
Hohmann, Lennart
supervisor
organization
course
BINP52 20212
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9102728
date added to LUP
2022-11-04 11:28:39
date last changed
2022-11-04 11:28:39
@misc{9102728,
  author       = {{Hohmann, Lennart}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Molecular and clinicopathological characterization of luminal HER2-enriched breast cancer}},
  year         = {{2022}},
}