How does HER2 overexpression result in changes in the cell cycle?

How does HER2 overexpression result in changes in the cell cycle?

Overexpressed HER2 receptor, combined preferentially with the HER3 receptor, sustains overactivity of cell-signaling networks leading to high levels of cell cycle regulators. This causes uncontrolled cell growth, proliferation and tumorigenesis.

What causes the HER2 gene to mutate?

HER2-positive breast cancer is not inherited. Instead, it’s considered a somatic genetic mutation. This type of mutation occurs after conception.

What cancers do we see HER2 overexpression in?

Amplification or overexpression of HER2 occurs in approximately 15–30% of breast cancers and 10–30% of gastric/gastroesophageal cancers and serves as a prognostic and predictive biomarker. HER2 overexpression has also been seen in other cancers like ovary, endometrium, bladder, lung, colon, and head and neck.

What is HER2/neu overexpression?

These receptors cooperate in the regulation of different processes, including cell proliferation, differentiation, and survival. 6,7. The HER2/neu gene is located on the 17q12-q21 chromosomal region and acts as an oncogene. Its amplification mainly translates into protein overexpression.

What happens when HER2 is activated?

HER2 is a membrane tyrosine kinase and oncogene that is overexpressed and gene amplified in about 20% of breast cancers. When activated it provides the cell with potent proliferative and anti-apoptosis signals and it is the major driver of tumor development and progression for this subset of breast cancer.

What is the normal function of HER2?

The HER2 gene makes HER2 proteins (also sometimes referred to as HER2/neu proteins). HER2 proteins are receptors on breast cells. Normally, HER2 receptors help control how a healthy breast cell grows, divides, and repairs itself.

Is it better to be HER2-negative or positive?

HER2-positive cancer tends to be poorer in terms of prognosis than HER2-negative cancer because: It grows faster. It is more likely to spread to the lymph nodes fast. It is at least two times more likely to return than HER2-negative tumors.

How is HER2 detected?

Most HER2 testing involves taking a sample of tumor tissue in a procedure called a biopsy. There are three main types of biopsy procedures: Fine needle aspiration biopsy, which uses a very thin needle to remove a sample of breast cells or fluid. Core needle biopsy, which uses a larger needle to remove a sample.

Is HER2 a hormone receptor?

Hormone Receptors and Human Epidermal Growth Factor (HER2) Expression in Fine-Needle Aspirates from Metastatic Breast Carcinoma – Role in Patient Management.

Is it better to have HER2-positive or negative?

Is HER2-positive breast cancer good or bad? HER2-positive cancer tends to be poorer in terms of prognosis than HER2-negative cancer because: It grows faster. It is more likely to spread to the lymph nodes fast.

How is HER2 overexpression related to breast cancer?

HER2 Overexpression in Cancers Most of the studies on HER2 have been carried out in breast cancer, after it was found to induce mammary carcinogenesis in vitro and in vivo. Amplification or overexpression of the HER2 gene occurs in approximately 15–30% of breast cancers.

What happens when breast cells have too many HER2 receptors?

All these extra HER2 genes tell breast cells to make too many HER2 receptors (HER2 protein overexpression). This makes breast cells grow and divide in an uncontrolled way. Breast cancers with HER2 gene amplification or HER2 protein overexpression are called HER2-positive in the pathology report.

How is HER2 gene amplification related to overall survival?

HER2 gene amplification is associated with shorter disease-free and overall survival in breast cancer. Slamon et al. established the prognostic significance of HER2 amplification in 189 human breast cancers. Amplification of HER2 gene was found to be a significant predictor of both overall survival (P< 0.001) and time to relapse (P< 0.0001).

What is the HER2 overexpression score in humans?

Table 1 Score Specimen HER2 overexpression assessment 0 No reactivity or membranous reactivity i Negative 1+ Faint membranous reactivity in >10% of t Negative 2+ Weak to moderate incomplete (basolateral Equivocal 3+ Moderate to strong incomplete (basolater Positive