To determine whether there was a similar increase in the ratio of FBLN1C to 1D in CAF compared to NAF, we assessed expression of FBLN1C and FBLN1D in the NAF and CAF cultures by QRT. Expression of both FBLN1C and FBLN1D isoforms was significantly lower in CAF than NAF (p = 0.008 and p = 0.011, respectively), and the ratio of 1C to 1D was similar in NAF PF-6463922 and CAF (Fig. 4). Because all FBLN1 antibodies available recognized both fibulin isoforms, we were unable to compare isoform expression in the stroma of the breast tissues by immunohistochemistry. Fig. 4 Expression of FBLN1 isoforms in NAF and CAF cultures. Expression of FBLN1C and FBLN1D was assessed by QRT using isoform-specific primer/probe sets in

all eight NAF and seven CAF. Expression of FBLN1C and FBLN1D was lower in CAF than NAF (p = 0.008 and p = 0.011, respectively, marked by asterisks). Furthermore, the ratio of FBLN1C to FBLN1D did not differ in NAF and CAF. The mean and standard deviation are shown Expression of FBLN1 is Higher in Estrogen Receptor-Positive than Estrogen Receptor-Negative Carcinomas Because expression of FBLN1C is induced by estrogen through estrogen receptor (ER) α [23, 24], we determined whether expression of FBLN1 differed in ERα-positive versus -negative carcinomas. Thirty-five breast cancers (the 32 cancers with corresponding normal breast plus three additional cancers without corresponding normal breast) were

SNX-5422 divided into ERα-positive and -negative subtypes, based on a the percentage of cells with nuclei that stained for ERα (i.e., less than 10% = ERα negative). Clinical and pathologic information related to these 35 cancers is summarized in Table 2. The Cediranib (AZD2171) immunoscores for FBLN1 were compared RAD001 between ERα-positive and -negative carcinomas. Using the A311 antibody, FBLN1 in the stroma was significantly higher in ERα-positive than -negative cancers (p = 0.032, Fig. 5). The mean FBLN1 immunoscore in cancer stroma

with the B-5 antibody was also higher in ERα-positive cancers, but this did not reach statistical significance (p = 0.097). Similarly, the mean FBLN1 immunoscore in cancer epithelium with either the A311 or B-5 antibody was higher in ERα-positive cancers, but this was not statistically significant (p = 0.307 and p = 0.167, respectively) (Fig. 5). These findings further support an association between FBLN1 expression, particularly in the stroma, and the presence of ERα in cancer epithelial cells. Fig. 5 Comparison of FBLN1 immunoscores in ERα-positive and -negative breast cancers. FBLN1 expression was assessed by immunohistochemistry in 35 breast cancers. Nineteen were ERα-negative, 14 were ERα-positive and the ER status was unknown in two. Expression of FBLN1 was higher in the fibroblastic stroma of ERα-positive cancers than ERα-negative cancers, but this was statistically significant with antibody A311 (p = 0.032) only.