Table 1.
Incidence of HER2-activating mutations by histology, hormone receptor status, and tumor tissue source for patients whose tumor samples successfully sequenced at GPS laboratory
| Positive for HER2 mutation, N (%) |
P | |
|---|---|---|
| Histology | ||
| Invasive ductal carcinoma (n = 309) | 5 (1.6%) | 0.026a |
| Invasive lobular carcinoma (n = 51) | 4 (7.8%) | |
| Invasive ductal/lobular carcinoma (n = 12) | 0 (0%) | |
| Otherb (n = 9) | 0 (0%) | |
| Hormone receptor status | ||
| ER+ and/or PR+ (n = 277) | 9 (3.2%) | 0.219 |
| ER− PR− HER2− (n = 82) | 0 (0%) | |
| Unknown (n = 17) | 0 (0%) | |
| Samples tested | ||
| Primary breast cancer (n = 256) | 6 (2.3%) | >0.99 |
| Metastatic site (n = 125) | 3 (2.4%) | |
| Total (n = 381) | 9 | |
a
Comparison between ductal carcinoma (n = 309) vs. lobular carcinoma (n = 51).
b
Others include metaplastic (n = 2); mucinous (n = 3); and unknown (n = 4).