HER2, chromosome 17 polysomy and DNA ploidy status in breast cancer; a translational study.

Breast cancer treatment depends on human epidermal growth factor receptor-2 (HER2) status, which is often determined using dual probe fluorescence in situ hybridisation (FISH). Hereby, also loss and gain of the centromere of chromosome 17 (CEP17) can be observed (HER2 is located on chromosome 17). CEP17 gain can lead to difficulty in interpretation of HER2 status, since this might represent true polysomy. With this study we investigated whether isolated polysomy is present and how this effects HER2 status in six breast cancer cell lines and 97 breast cancer cases, using HER2 FISH and immunohistochemistry, DNA ploidy assessment and multiplex ligation dependent probe amplification. We observed no isolated polysomy of chromosome 17 in any cell line. However, FISH analysis did show CEP17 gain in five of six cell lines, which reflected gains of the whole chromosome in metaphase spreads and aneuploidy with gain of multiple chromosomes in all these cases. In patients' samples, gain of CEP17 indeed correlated with aneuploidy of the tumour (91.1%; p < 0.001). Our results indicate that CEP17 gain is not due to isolated polysomy, but rather due to widespread aneuploidy with gain of multiple chromosomes. As aneuploidy is associated with poor clinical outcome, irrespective of tumour grade, this could improve future therapeutic decision making.

T-cell Landscape in a Primary Melanoma Predicts the Survival of Patients with Metastatic Disease after Their Treatment with Dendritic Cell Vaccines.

Tumor-infiltrating lymphocytes appear to be a predictor of survival in many cancers, including cutaneous melanoma. We applied automated multispectral imaging to determine whether density and distribution of T cells within primary cutaneous melanoma tissue correlate with survival of metastatic melanoma patients after dendritic cell (DC) vaccination. CD3(+) T cell infiltration in primary tumors from 77 metastatic melanoma patients was quantified using the ratio of intratumoral versus peritumoral T-cell densities (I/P ratio). Patients with longer survival after DC vaccination had stronger T-cell infiltration than patients with shorter survival in a discovery cohort of 19 patients (P = 0.000026) and a validation cohort of 39 patients (P = 0.000016). I/P ratio was the strongest predictor of survival in a multivariate analysis including M substage and serum lactate dehydrogenase level. To evaluate I/P ratio as a predictive biomarker, we analyzed 19 chemotherapy-treated patients. Longer survival times of DC-vaccinated compared with chemotherapy-treated patients was observed for high (P = 0.000566), but not low (P = 0.154) I/P ratios. In conclusion, T-cell infiltration into primary melanoma is a strong predictor of survival after DC vaccination in metastatic melanoma patients who, on average, started this therapy several years after primary tumor resection. The infiltration remains predictive even after adjustment for late-stage prognostic markers. Our findings suggest that the I/P ratio is a potential predictive biomarker for treatment selection. Cancer Res; 76(12); 3496-506. ©2016 AACR.