2.8. Case Series

Samples collected at our Institution were used for immunohistochemical detection of TG2. Ten patients with histologically confirmed DCIS, median age 60 years (range 40–66) were included in the present study. The DCIS median size was 7 mm (range 5–20 mm); six tumors were defined as grade-3, three as grade-2 and one was grade-1. Four patients had estrogen receptor-positive tumors by immunohistochemistry and six were defined as human epidermal growth factor 2 (HER)-2 positive by immunohistochemistry and FISH analysis. A written informed consent signed by each patient authorized the use of material left over from the diagnosis for research purposes. Correlations with clinical data were investigated in publicly available datasets and in a small case series from our Institution.

TGM2 expression in stromal tissue adjacent to normal or tumor breast cells was evaluated in two publicly available datasets whose normalized data were downloaded from GEO with accession numbers {"type":"entrez-geo","attrs":{"text":"GSE14548","term_id":"14548"}}GSE14548 [24] and {"type":"entrez-geo","attrs":{"text":"GSE26910","term_id":"26910"}}GSE26910 [25]. Survival analysis for TGM2 was performed using METABRIC [26] and a combined dataset derived from publicly available gene expression data retrieved from GEO ({"type":"entrez-geo","attrs":{"text":"GSE2034","term_id":"2034"}}GSE2034, {"type":"entrez-geo","attrs":{"text":"GSE2990","term_id":"2990"}}GSE2990, {"type":"entrez-geo","attrs":{"text":"GSE5327","term_id":"5327"}}GSE5327, and {"type":"entrez-geo","attrs":{"text":"GSE11121","term_id":"11121"}}GSE11121). For the combined dataset, gene expression data were merged similarly as described in Callari et al. [13].