Focus on HER2 and ovarian cancer

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How common is HER2 overexpression/amplification in ovarian cancer?

A number of studies have investigated the incidence of HER2 overexpression in ovarian cancer, with widely varied results. Selected studies appear in the table below.

Source	N	Definition of HER2 overexpression	Percentage of tumors overexpressing HER2
Berchuck et al, Cancer Res, 1990²¹	73	3+ or higher staining by IHC	32%
Pils et al, Br J Cancer, 2007²²	148	2+ or higher staining by IHC	28%
Slamon et al, Science, 1989¹	120	At least 2 times the normal number of gene copies by Southern blot	26%
Bookman et al, J Clin Oncol, 2003²³	837	2+ or higher staining by IHC	11%
Steffensen et al, Int J Gynecol Cancer, 2007²⁴	160	2+ or higher staining by IHC	11% (7% 2+, 4% 3+)
Dimova et al, Int J Gynecol Cancer, 2006²⁵	1006	At least 3 times the number of normal gene signals by fluorescence in situ hybridization (FISH)	8% (an additional 7% had overexpression at less than 3 times the number of normal gene signals)

The wide range of reported frequencies may be due to¹⁴:
- Differences in methods of HER2 detection
- The degree of overexpression required for a definition of “positive” in each study
- The tissues used for analysis

Is there a relationship between HER2 and estrogen in ovarian cancer?

Although the relationship between HER2 and the estrogen receptor (ER) is well characterized in breast cancer, less is known about interactions between the 2 receptors in ovarian cancer.

A 2007 preclinical study indicates that there may be cross-talk between HER2 and ER in ovarian cancer²⁶
- In ovarian tumor cell lines, estrogen induced phosphorylation of HER2, initiating downstream signaling pathways

Next Section: HER2 as a potential therapeutic target

References

Research HER Pathways

HER2