Table 2. Y chromosome loss in male breast cancer patients.
| Patient Number | Tumor Cellularity (%) | Positive ddPCR Droplets | Ratio Y/X | ddPCR Interpretation | FISH | |
|---|---|---|---|---|---|---|
| Y Chr Taqman | X Chr Taqman | |||||
| 01 | 70 | 7 | 524 | 0.013 | Y Loss | Y Loss |
| 02 | 60 | 6 | 114 | 0.053 | Y Loss | Y Loss |
| 03 | 80 | 357 | 1009 | 0.354 | Equivocal | Y Retention * |
| 04 | 80 | 217 | 566 | 0.383 | Equivocal | Y Retention * |
| 05 | 60 | 84 | 205 | 0.410 | Equivocal | Y Loss |
| 06 | 60 | 54 | 116 | 0.466 | Equivocal | Unevaluable |
| 07 | 70 | 47 | 73 | 0.644 | Y Retention | Y Retention |
| 08 | 70 | 17 | 24 | 0.708 | Y Retention | Y Retention |
| 09 | 70 | 158 | 196 | 0.806 | Y Retention | Y Retention |
| 10 | 80 | 57 | 52 | 1.096 | Y Retention | Y Retention |
| 11 | 70 | 134 | 117 | 1.145 | Y Retention | Y Retention |
| 12 | 70 | 334 | 214 | 1.561 | Y Retention | Y Retention |
| 13 | 70 | 482 | 293 | 1.645 | Y Retention | Y Retention |
| 14 | 60 | 156 | 91 | 1.714 | Y Retention | Unevaluable |
| 15 | 80 | 2067 | 1188 | 1.740 | Y Retention | Y Retention |
| 16 | 50 | 53 | 23 | 2.304 | Y Retention | Unevaluable |
| 17 | 70 | 252 | 86 | 2.930 | Y Retention | Y Retention |
| Cohort 1 patient with Y loss | 80 | 101 | 523 | 0.193 | Y Loss | Y Loss |
| Male gDNA | NA | 2628 | 2720 | 0.966 | Y Retention | Male Control |
| Female gDNA | NA | 0 | 3451 | 0.000 | No Y | Female Control |
Tumor gDNA was extracted from FFPE tissue slides from male breast cancer patients and analyzed using ddPCR Taqman probes specific for X and Y chromosomes. Fourteen of 17 ddPCR-analyzable samples were validated by FISH; three patients had FFPE tissue that could not be validated with FISH.
*
Denotes male breast cancer patients who have duplication of X chromosome.