HIN-1: a New Epigenetic Biomarker Crucial for Therapy Selection in Glioblastoma Multiforme.

Glioblastoma multiforme (GBM) is the most common brain tumor in adults. The role of high in normal-1 (HIN-1) as a potential biomarker in combating this disease is being described for the first time in this study. A combination of O6-methylguanine DNA methyltransferase (MGMT) and HIN-1 methylation could be a possible biomarker in therapy choice. Interestingly, survival data shows a similar trend for the methylation of MGMT and for unmethylation of HIN-1 and vice versa. Eighty-eight paraffin-embedded brain tumors were analyzed to screen methylation rates of different genes and evaluate the association between genes methylation and clinicopathologic variables. Our study is the first of its kind to indicate that MGMT and HIN-1 methylation status are inverted (97.7% of methylated ones) and could be new markers in the study of GBM prognosis, especially in the therapy selection.

Whether to determine HER2 status for breast cancer in the primary tumour or in the metastasis.

Trastuzumab has substantially changed the prognosis of breast carcinomas. As HER2 over-expression/amplification is a prerequisite for treatment with trastuzumab, an accurate assessment of HER-2 status is the first step for successful treatment. In metastatic breast cancer, we routinely assess HER2 expression in the primary tumour, assuming that HER2 status remains stable through cancer progression. However, it is frequent to find reports that describe discordance between HER2 expression in primary and metastatic tumours. The aim of this paper was to verify whether HER2 status of breast carcinomas is maintained in the corresponding axillary metastasis. Immunohistochemistry was performed on 52 breast carcinomas and their matched axillary metastasis. HercepTest results were concordant in 46 out of 52 cases (88.5%). FISH proved that the differences observed were clinically relevant in only one of the 52 cases studied (98% concordance). We concluded that HER2 status was stable during axillary metastatic progression. Evaluation of gene HER2 status in axillary metastasis rather than in the primary can be useful in certain situations, e.g., small invasive component intimately mixed with in situ component and difficult to recognize in dark field, no tumor after biopsy, or axillary relapse (in this case we can find occasional de novo amplifications susceptible to trastuzumab treatment).

Immunohistochemical demonstration of neuronal and astrocytic markers and oncofoetal antigens in retinoblastomas.

General opinion is that retinoblastomas, though not everyone agrees with that view. Some authors suggest that retinoblastomas are derived from a primitive retinal cell able to differentiate into both neuronal and glial cell lines. The aim of the present work was to study immunohistochemically the expression of neuronal and astrocytic markers in retinoblastomas and at the same time the presence of the oncofoetal antigens carcinoembryonic antigen (CEA) and alpha Foeto Protein (AFP), since patients with retinoblastomas often show high oncofoetal antigen in serum levels. For this purpose we employed the streptavidin-biotin immunoperoxidase technique in 13 cases of retinoblastoma to evaluate the presence and distribution of neuron-specific enolase (NSE), neurofilament protein (NF), glial fibrillary acidic protein (GFAP), S-100 protein, CEA and AFP. All 13 tumours studied stained for NSE. Seven of them showed GFAP- and S-100 positive perivascular glial cells as well as cells distributed randomly in the tumour that were interpreted as non tumour cells. All 13 retinoblastomas lacked detectable NF, CEA, and AFP. These results support the idea that retinoblastomas are neuronal tumours, although retinal glial cells may become incorporated in the tumour and proliferate in response to the tumour.