TY - JOUR
T1 - Influence of biospecimen variables on proteomic biomarkers in breast cancer
AU - Meric-Bernstam, Funda
AU - Akcakanat, Argun
AU - Chen, Huiqin
AU - Sahin, Aysegul
AU - Tarco, Emily
AU - Carkaci, Selin
AU - Adrada, Beatriz E.
AU - Singh, Gopal
AU - Do, Kim Anh
AU - Garces, Zerzhinski M.
AU - Mittendorf, Elizabeth
AU - Babiera, Gildy
AU - Bedrosian, Isabelle
AU - Hwang, Rosa
AU - Krishnamurthy, Savitri
AU - Symmans, William F.
AU - Gonzalez-Angulo, Ana Maria
AU - Mills, Gordon B.
PY - 2014/7/15
Y1 - 2014/7/15
N2 - Background: PI3K/Akt/mTOR signaling is being actively pursued as a therapeutic target for breast cancer. We sought to determine if tumor heterogeneity and biospecimen variables affect the evaluation of PI3K/Akt/mTOR pathway markers. Methods: Intraoperative image-guided core-needle biopsies (CNB), and central and peripheral surgical tumor specimens were prospectively collected in 53 patients with invasive breast cancer. Specimens were assessed with reverse-phase protein arrays (RPPA) and immunohistochemistry (IHC). Results: There was a moderate or strong correlation between the expression of 149 (97%) of the 154 different RPPA markers in the center and periphery. Correlation was higher for smaller tumors, in patients whodid not undergo neoadjuvant therapy, and with shorter cold ischemia time. Of 154 markers, 132 (86%) were not statistically different between the center and periphery, and 97 (63%) were not different between the CNB and the surgical specimen (average of the central and peripheral specimen). pAkt S473 and PTEN had a significant correlation between central and peripheral specimens, and between CNB and surgical specimen. However, pAkt S473, pS6 S235/236, and pS6 240/244 levels were significantly higher in CNB than the central specimens both by RPPA and by IHC. Conclusions: Most individual proteomic biomarkers studied do not have significant intratumoral heterogeneity. However, protein and phosphoprotein levels are affected by biospecimen type and other preanalytic variables. PI3K pathway activation is greater in CNB compared with postexcision surgical samples suggesting a potential loss of phosphorylation during surgical manipulation, or with cold ischemia of surgical specimens.
AB - Background: PI3K/Akt/mTOR signaling is being actively pursued as a therapeutic target for breast cancer. We sought to determine if tumor heterogeneity and biospecimen variables affect the evaluation of PI3K/Akt/mTOR pathway markers. Methods: Intraoperative image-guided core-needle biopsies (CNB), and central and peripheral surgical tumor specimens were prospectively collected in 53 patients with invasive breast cancer. Specimens were assessed with reverse-phase protein arrays (RPPA) and immunohistochemistry (IHC). Results: There was a moderate or strong correlation between the expression of 149 (97%) of the 154 different RPPA markers in the center and periphery. Correlation was higher for smaller tumors, in patients whodid not undergo neoadjuvant therapy, and with shorter cold ischemia time. Of 154 markers, 132 (86%) were not statistically different between the center and periphery, and 97 (63%) were not different between the CNB and the surgical specimen (average of the central and peripheral specimen). pAkt S473 and PTEN had a significant correlation between central and peripheral specimens, and between CNB and surgical specimen. However, pAkt S473, pS6 S235/236, and pS6 240/244 levels were significantly higher in CNB than the central specimens both by RPPA and by IHC. Conclusions: Most individual proteomic biomarkers studied do not have significant intratumoral heterogeneity. However, protein and phosphoprotein levels are affected by biospecimen type and other preanalytic variables. PI3K pathway activation is greater in CNB compared with postexcision surgical samples suggesting a potential loss of phosphorylation during surgical manipulation, or with cold ischemia of surgical specimens.
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U2 - 10.1158/1078-0432.CCR-13-1507
DO - 10.1158/1078-0432.CCR-13-1507
M3 - Article
C2 - 24895461
AN - SCOPUS:84904400245
SN - 1078-0432
VL - 20
SP - 3870
EP - 3883
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 14
ER -