Final answer:
Elevated estrogen levels are associated with the development of breast cancer, which can promote excessive cell growth. The hormone plays a key role in female reproductive health but can be carcinogenic in imbalanced states. HER2 overexpression is another hormonal abnormality implicated in breast cancer, targeted by drugs like Herceptin.
Step-by-step explanation:
The hormonal abnormality associated with the development of breast cancer is elevated levels of estrogen. During various phases of a woman's life, such as menopause or the menstrual cycle, estrogen levels can fluctuate. Persistent high levels of estrogen can lead to an increased risk of endometrial and breast cancer. Estrogen is crucial for the development of female secondary sexual characteristics and the reproductive cycle. However, this hormone can act similarly to non-mutagenic carcinogens by promoting excessive cell growth when in a hyperestrogenic state.
Moreover, hormonal imbalances such as the overexpression of HER2, a cell-surface receptor, have been linked to the development of breast cancer in approximately 20 percent of cases. Treatments like Herceptin (trastuzumab), which targets HER2, have helped improve survival rates for patients with metastatic breast cancer.
It can be seen that hormones play a complex role in female health, where they support necessary physiological functions but can also contribute to the development of diseases like cancer under abnormal conditions.