Table 2.
Clinical pathological features of whole case series according to 2019 WHO classification
| NET/NEC (37) | Other NE differentiated BC (26) | P value | Total | ||
|---|---|---|---|---|---|
| Age (years) | Median (interval) | 73 (45–93) | 75 (46–86) | 0.881 | 74 (45–85) |
| Histological grade | 1 | 9 | 9 | 0.560 | 17 |
| 2 | 20 | 15 | 35 | ||
| 3 | 8 | 3 | 11 | ||
| Vascular invasion | No | 20 | 15 | 0.775 | 35 |
| Yes | 17 | 11 | 28 | ||
| pT | 1 | 24 | 14 | 0.416 | 38 |
| 2 | 10 | 11 | 21 | ||
| 3 | 1 | 1 | 2 | ||
| 4 | 2 | 0 | 2 | ||
| pN | 0 | 26 | 19 | 0.791 | 45 |
| 1 | 8 | 6 | 14 | ||
| 2 | 3 | 1 | 4 | ||
| ER | Median (interval) | 99 (10–100) | 95 (15–100) | 0.452 | 99 (10–100) |
| PgR | Median (interval) | 65 (0–100) | 80 (0–99) | 0.584 | 60 (0–100) |
| HER2 | 0 | 23 | 15 | 0.829 | 38 |
| 1+ | 9 | 6 | 15 | ||
| *2+ | 5 | 5 | 10 | ||
| Surrogate molecular profile | Luminal A | 18 | 15 | 0.479 | 33 |
| Luminal B | 19 | 11 | 30 | ||
| Ki67 index | < 20 | 21 | 16 | 0.704 | 37 |
| ≥ 20 | 16 | 10 | 26 | ||
| Ki67 index | Median (interval) | 18 (1–80) | 16 (2–45) | 0.740 | 18 (1–80) |
| CGA | Negative | 13 | 11 | 0.564 | 24 |
| Focal/diffuse positivity | 24 | 15 | 39 | ||
| SYN | Negative | 0 | 3 | 0.034 | 3 |
| Focal/diffuse positivity | 37 | 23 | 60 | ||
| INSM1 | Negative | 9 | 2 | 0.087 | 11 |
| Positive | 28 | 24 | 52 | ||
| Surgery | Conservative | 18 | 18 | 0.722 | 36 |
| Mastectomy | 19 | 8 | 27 | ||
| Type of therapy (13 missing) | HT | 25 | 18 | 0.506 | 43 |
| HT and/or CT | 5 | 2 | 7 | ||
| Recurrences (9 missing) | No | 28 | 20 | 0.236 | 48 |
| Yes | 5 | 1 | 6 | ||
| Died of disease (3 missing) | No | 25 | 21 | 0.105 | 46 |
| Yes | 11 | 3 | 14 |
NE neuroendocrine, BC breast cancer, ER estrogen receptor, PgR progesterone receptor, CGA Chromogranin A, SYN Synaptophysin, HT hormonal therapy, CT chemotherapy
*All cases that were assessed as 2+ underwent FISH analyses that resulted negative for HER2 gene status