Introduction: Rectal cancer patients with a cT3N+M0 tumor
stage responds to the neo-adjuvant therapy, which causes necrosis and
inflammation in situ. We cannot predict which patients will response.
Methods: We collected blood and tissue samples at three time
points: at diagnosis, at the end of the first CT cycle and at 8 week after
the end of the therapy (coinciding with the surgical resection time of the
tumour). At each time point we characterized circulating monocytes by
flow cytometry, infiltrating macrophages by immunohistochemistry and
selected inflammatory molecules in serum and plasma.
Results: We recruited 28 pts, with No substantial changes were detectable
in the number of circulating monocytes. In contrast we observed
a clear expansion of CD14/CD86 and CD14/CD163 double
positive subsets. In fact we observed that in the responder patients the
expansion of the CD14/86 subset was clear in the first weeks of treatment
and decreased there after. The immunohistochemical study revealed
a massive tumoral infiltration by macrophages that displayed
clear features of alternative M2 polarization.
Conclusion: These data suggest that neoadjuvant therapy modulates
the cellular components of innate immune responses that could
represent valuable predictive factors.