Table 3.

Correlation between the pCR rate and biomarkers of enhanced immune activation in both tumor and immune cells.

Correlation between the pCR rate and PD-L1 status of tumor samples using the TPS before chemoradiotherapy
	pCR rate in MSS patients		pCR rate in MSI-H patients
	(N = 38)		(N = 5)
PD-L1 (TPS)a ≥1%	75% (6/8)b		—
PD-L1 (TPS) <1%	17% (5/30)b		60% (3/5)

Correlation between the pCR rate and the CD8/eTreg ratio in tumor-infiltrating lymphocytes (TILs) before chemoradiotherapy
	pCR rate in MSS patients		pCR rate in MSI-H patients
	(N = 24)		(N = 5)
CD8/eTreg ratio before CRT ≥2.5	78% (7/9)c		67% (2/3)
CD8/eTreg ratio before CRT <2.5	13% (2/15)c		50% (1/2)

pCR rate by combined analysis of both PD-L1 expression using the TPS and the CD8/eTreg ratio before chemoradiotherapy in patients with MSS LARC (N = 24)
	CD8/eTreg ≥ 2.5	CD8/eTreg < 2.5	Total
PD-L1 (TPS) ≥1%	100% (5/5)	33% (1/3)	75% (6/8)
PD-L1 (TPS) <1%	50% (2/4)	8% (1/12)	19% (3/16)

Abbreviations: pCR, pathologic complete response; TPS, tumor proportion score; CD8/eTreg, CD8+ T cell/effector regulatory T cell; TILs, tumor-infiltrating lymphocytes; MSS, microsatellite-stable; MSI-H, microsatellite-instability–high; LARC, locally advanced rectal cancer.

^aTPS = (PD-L1 positive tumor cells/all tumor cells) × 100.

^b P = 0.004, Fisher's exact test.

^c P = 0.003, Fisher's exact test.