TY - JOUR
T1 - PD-L1 expression in colorectal cancer defines three subsets of tumor immune microenvironments
AU - Valentini, Anna Maria
AU - Di Pinto, Federica
AU - Cariola, Filomena
AU - Guerra, Vito
AU - Giannelli, Gianluigi
AU - Caruso, Maria Lucia
AU - Pirrelli, Michele
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Objectives: We investigated the PD-L1 expression in colorectal cancer (CRC) and in its microenvironment. Results: PD-L1 was expressed in neoplastic cells (NCs) and tumor-infiltrating immune cells (IICs). All samples PD-L1+ on NCs were also on IICs. Three types of cancers could be grouped: group A(NCs-/ IICs-); group B (NCs-/ IICs+); group C (NCs+/IICs+). To group A belong tumors characterized by poorly immunogenic competence, poor immune response but massive granulocyte infiltrate, justifying the absence of PD-L1 as an immunoinhibitor receptor. To Group B probably belong more immunogenic CRCs, justifying the strong IICs-mediated immune response, and up-regulation of PD-L1 expression only on IICs. To group C belong CRCs probably characterized by a large amount of tumor neoantigens resulting in a marked infiltration of lymphocytes and PD-L1 upregulation also in NCs. Materials and Methods: Sixty-three colorectal cancer specimens from a cohort of 61 patients were retrospectively reviewed. Thirty-seven MSS and 26 MSI-H CRCs enrolled in this study. Immunohistochemical staining to PD-L1 was performed by using MAb E1L3N. Conclusions: Our study calls attention to the importance to assess PD-L1 expression in tumor microenvironment also evaluating type and density of infiltrating immune cells to better stratify CRCs with different immunological patterns.
AB - Objectives: We investigated the PD-L1 expression in colorectal cancer (CRC) and in its microenvironment. Results: PD-L1 was expressed in neoplastic cells (NCs) and tumor-infiltrating immune cells (IICs). All samples PD-L1+ on NCs were also on IICs. Three types of cancers could be grouped: group A(NCs-/ IICs-); group B (NCs-/ IICs+); group C (NCs+/IICs+). To group A belong tumors characterized by poorly immunogenic competence, poor immune response but massive granulocyte infiltrate, justifying the absence of PD-L1 as an immunoinhibitor receptor. To Group B probably belong more immunogenic CRCs, justifying the strong IICs-mediated immune response, and up-regulation of PD-L1 expression only on IICs. To group C belong CRCs probably characterized by a large amount of tumor neoantigens resulting in a marked infiltration of lymphocytes and PD-L1 upregulation also in NCs. Materials and Methods: Sixty-three colorectal cancer specimens from a cohort of 61 patients were retrospectively reviewed. Thirty-seven MSS and 26 MSI-H CRCs enrolled in this study. Immunohistochemical staining to PD-L1 was performed by using MAb E1L3N. Conclusions: Our study calls attention to the importance to assess PD-L1 expression in tumor microenvironment also evaluating type and density of infiltrating immune cells to better stratify CRCs with different immunological patterns.
KW - Colorectal cancer
KW - Immunohistochemistry
KW - Microsatellite instability
KW - PD-1
KW - PD-L1
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U2 - 10.18632/oncotarget.24196
DO - 10.18632/oncotarget.24196
M3 - Article
AN - SCOPUS:85041469438
VL - 9
SP - 8584
EP - 8596
JO - Oncotarget
JF - Oncotarget
SN - 1949-2553
IS - 9
ER -