Clinical Impact of X-Ray Repair Cross-Complementary 1 (XRCC1) and the Immune Environment in Colorectal Adenoma–Carcinoma Pathway Progression

Abstract

Colorectal cancer (CRC) can develop via a hypermutagenic pathway characterized by frequent somatic DNA base-pair mutations. Alternatively, the immunogenicity of tumor cells themselves may influence the anticancer activity of the immune effector cells. Impaired DNA repair mechanisms drive mutagenicity, which then increase the neoantigen load and immunogenicity. However, no studies have analyzed immune checkpoint protein expression, particularly programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1), in adenoma-carcinoma progression and its relationship with the emergence of other DNA repair gene mutation. Materials and Methods: We investigated mutations of 10 genes involved in DNA repair function: XRCC1, TP53, MLH1, MSH, KRAS, GSTP, UMP, MTHF, DPYD, and ABCC2. We performed sequencing to determine mutations and immunohistochemistry of immune checkpoints in clinical samples and determined changes in XRCC1 expression during progression through the adenoma-carcinoma pathway. We further investigated the prognostic associations of gene XRCC1 according to the expression, mutational profile, and immune profile using The Cancer Genome Atlas-colon adenocarcinoma (TCGA-COAD) dataset. Results: From clinical samples, XRCC1 mutation demonstrated the strongest association with adenomas with a mutation frequency of 56.2% in adenomas and 34% in CRCs (p =0.016). XRCC1 was abnormally expressed and altered by mutations contributing to adenoma carcinogenesis. High expression of XRCC1, CD4, FOXP3, and PD-1/PD-L1 showed an overall upward trend with increased lesion severity (all p < 0.01). PD-1/PD-L1 expression and CD4+ intraepithelial lymphocytes (IELs) correlated with cytological dysplasia progression, specifically in patients with wild-type XRCC1 (all p < 0.01), whereas FOXP3 expression was independently associated with adenoma-carcinoma progression. From TCGA-COAD analysis, XRCC1 expression was associated with patients survival, tumor-infiltrating lymphocytes and immune marker expression. Conclusion: Increased IEL density and PD-1/PD-L1 expression correlate with cytological dysplasia progression and specifically with the XRCC1 mutation status in CRC. Our findings support a stepwise dysplasia-carcinoma sequence of adenoma carcinogenesis and an XRCC1 hypermutated phenotypic mechanism of lesions.

CILP2: A prognostic biomarker associated with immune infiltration in colorectal cancer

“…Immunohistochemistry was performed to determine CILP2 expression in the TMA sections and paraffin-embedded tissue pairs, as described in previous studies [ 13 ]. Briefly, tissue sections were dewaxed, repaired, closed, and then incubated with anti-CILP2 (Invitrogen, UAS) overnight at 4 °C.…”

ICOS/ICOSLG and PD-1 Co-Expression is Associated with the Progression of Colorectal Precancerous- Carcinoma Immune Microenvironment

“…IHC staining to detect ICOS, ICOSLG, PD-1, and PD-L1, cluster of differentiation CD4 and FoxP3 was performed following the protocol reported in a previous study. 18 Briefly, after deparaffinization, rehydration, antigen retrieval, endogenous peroxidase inactivation and non-specific binding blockade, 4 µM-thick serial sections were incubated with primary antibody anti-ICOS (ab224644, Abcam, Cambridge, UK), anti-ICOSLG (ab233151, Abcam, Cambridge, UK), anti-PD-1 (GT228107, GeneTech, Shanghai, China), anti-PD-L1 (GT228007, GeneTech, Shanghai, China), anti-Foxp3 (ab215206, Abcam, Cambridge, UK), and anti-CD4 (ab183685, Abcam, Cambridge, UK) at 4°C overnight. The mIHC was carried out by using the Five-color multiplex fluorescent IHC kit (abs50013, Absin, Shanghai, China) based on the manufacturer's instructions to characterize the expressions and localization of PD-1, ICOS and ICOSLG in CRC and precancerous tissues.…”

“…34 In a previous study, we confirmed that increased TIL density and PD-1/PD-L1 expression correlated with cytological dysplasia progression. 18 ICOS is generally involved in the production, proliferation, and survival of Tregs, providing them with a strong suppressive capability. 35,36 With respect to ICOS assessment in our study, the counts of single positive cells in the stroma were increased in precancerous lesions according to PD-1 expression, but no differences were observed at different PD-L1 expression levels.…”

Personalised neoantigen‐based therapy in colorectal cancer

“…The development of CRC mainly involves three signalling pathways, including chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylation phenotype (CIMP) 3‐5 . CIN is the most classical and common molecular pathway involved in CRC, accounting for 75% of all CRC cases.…”

“…2 The development of CRC mainly involves three signalling pathways, including chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylation phenotype (CIMP). [3][4][5] CIN is the most classical and common molecular pathway involved in CRC, accounting for 75% of all CRC cases. It is characterised by chromosomal alterations, including somatic copy number alterations due to deletion, aneuploid loss, insertion and amplification.…”