Expression of CD151/Tspan24 and integrin alpha 3 complex in aid of prognostication of HER2-negative high-grade ductal carcinoma in situ.

The pro-tumorigenic and pro-metastatic functions of the tetraspanin protein CD151 (Tspan24) are thought to be dependent on its ability to form complexes with laminin-binding integrin receptors (i.e. alpha6beta1, alpha3beta1, alpha6beta4). We have previously reported that in invasive ductal carcinoma (IDC), CD151/alpha3beta1 complex was of prognostic value in patients with HER2-negative tumors. Extrapolating these findings to the pre-invasive setting, we aimed to make an assessment of a potential relationship between expression of the CD151/alpha3beta1 complex in DCIS and Van Nuys prognostic index (VNPI) in high-grade ductal carcinoma in situ (DCIS) in relation to the HER2 status. Protein distributions were analyzed in 49 samples of pure DCIS using immunohistochemistry. For each case immunoreactivity was assessed in at least 5 ducts (325 ducts in total) and an average score was taken for statistical analyses. When analyzed in the whole cohort, there was no statistical association between the VNPI and any of the proteins scored either separately or in combination. When stratified according to the HER2 status, in the HER2-negative subgroup, CD151 assessed in combination with alpha3beta1 was significantly correlated with VNPI (P = 0.044), while neither protein analyzed individually showed any significant link with the prognostic index. Expression of the CD151/alpha3beta1 complex in HER2-negative DCIS might reflect tumor behavior relevant to the patient outcome and thus might aid prognostication of the disease.