Laura Paleari

Supplementary Table 2 shows the pooled-arm analyses isolating the effects of aspirin and metformin on global NFκB expression, adjusted for baseline values.

Supplementary Table 1 shows baseline immunohistochemical expression of NFκB, EGFR, Ki67 and pS6K in normal right and left colonic mucosa by treatment arm.

Main baseline patient characteristics.

Supplementary Table 4 describes the representativeness of the study participants with respect to sex, age, race/ethnicity and geography.

Number of adverse events and grade by treatment arm.

Participant flow diagram including surrogate endpoints.

Supplementary Table 3 shows the pooled-arm analyses isolating the effects of aspirin and metformin on global Ki67 expression, adjusted for baseline values.

Purpose: Aspirin (Asa) and metformin (Met) have shown preventive efficacy in colorectal cancer. Preclinical data suggest convergence on NF-κB/PI3K–mTOR signaling and potential synergy. The ASAMET phase II trial tested this hypothesis in patients with resected stage I to III colorectal cancer. Patients and Methods: In a 2 × 2 factorial, multicenter, double-blind study (EudraCT 2015-004824-77; NCT03047837), 51 patients were randomized to placebo, Asa 100 mg once daily, Met 850 mg twice daily, or AsaMet for 12 months. Biopsies of normal colonic mucosa and fasting blood samples were obtained at baseline and 12 months. NF-κB (primary endpoint), Ki67, EGFR, and pS6K were assessed by IHC. Results: After 12 months, compared with placebo, Met reduced global NF-κB by −9.04 [95% confidence interval (CI), −17.55 to −0.54; P = 0.04], whereas Asa alone was inactive (−3.58; 95% CI, −12.15 to 4.99; P = 0.41), and AsaMet showed a nonsignificant reduction (−8.88; 95% CI, −18.86 to 1.10; P = 0.08). Pooled analyses confirmed a Met-driven effect (Met vs. non-Met: −7.29; 95% CI, −13.79 to −0.79; P = 0.03), with no impact of Asa (P = 0.73). Ki67 and pS6K were unchanged globally; however, AsaMet increased right-sided Ki67 (12.48; 95% CI, 0.45–24.51; P = 0.04). No treatment modulated pS6K. Toxicity was manageable, and no serious adverse events occurred. Conclusions: Met reduces NF-κB expression in normal colorectal mucosa of survivors of colorectal cancer, supporting its potential as a low-toxicity preventive agent. Asa did not favorably affect mucosal biomarkers. These findings support tissue-based endpoints and further evaluation of Met for colorectal cancer prevention. Significance: The ASAMET trial provides the first randomized evidence that Met significantly modulates NF-κB expression in histologically normal colorectal mucosa of survivors of colorectal cancer. This finding supports a biologically plausible mechanism of action in secondary cancer prevention that could be exploited in the postadjuvant setting. Asa, by contrast, did not favorably affect any mucosal biomarker endpoint in this population. These results may support a phase III study of Met in this setting. Trial Registration: ClinicalTrials.gov Identifier: NCT03047837; EudraCT number: 2015-004824-77.

Background: Natural killer (NK) cells are innate lymphocytes endowed with potent cytotoxic activity. The presence of tumor-associated NK cells has been correlated with better prognosis in several solid tumors including colorectal cancer (CRC). This malignant disease is the second cause of cancer death worldwide and is in urgent need for novel approaches to improve current immunotherapies. Since CRC microenvironment can induce NK cell dysfunction and hinder cancer control, understanding tumor-associated NK cell features is mandatory to fully unlock their immunotherapeutic potential.Purpose: Our study aims at elucidating the molecular and functional characteristics of tumor-associated NK cells in CRC focusing on the expression of immune checkpoints that critically regulate NK cell function. We performed an in-depth cytofluorimetric analysis of tumor-associated NK cells obtained by tissue dissociation of samples derived from 80 CRC patients comparing tumor with matched tumor-free tissue and peripheral blood, stratifying patients by tumor stage or MSI/MSS condition. Tumor tissue was also analyzed by immunohistochemistry.Results: NK cells expressing immune checkpoints (i.e., KIR, NKG2A and TIM-3) were significantly enriched in tumor compared to tumor-free tissue, and an increase in PD-1⁺ NK cells was observed in tumors compared to peripheral blood and tumor-free tissue, indicating TME-induced modulation. Notably, tumor-associated PD-1⁺ NK cells characterized MSI rather than MSS CRC. In addition, tumor-associated NK cells also expressed tissue residency markers (CD103 and/or CD49a) and displayed a distinct profile also including the PD-1⁺ NK cell subset in MSI CRC, possibly representing NK cells recruited from circulation, retained in tumors, and reconfigured by TME signals. Importantly, tissue resident NK cells adequately expressed activating NK receptors and cytotoxic molecules.Conclusions: These results suggest, together with an increased PD-L1 expression on MSI tumor cells, that the efficacy of immunotherapies in MSI CRC based on PD-1/PD-L1 blockade could also rely on a superior anti-tumor potential of PD-1⁺ NK cells. Conversely, MSS CRC, in which tumor-associated PD-1⁺ NK cells are scarce, could benefit more from immunotherapies blocking NKG2A and/or KIRs. Thus, novel approaches based on NK cell features related to CRC type, fully exploiting circulating and resident NK cell anti-tumor activity, could be key to next-generation therapies.

The intention of this Special Issue is to highlight research that aims to recognize cancer’s complexity to better prevent or treat its occurrence