Table 1 Criteria used for grading the quality of evidence of candidate genetic variants related to the pharmacodynamic pathways of immunosuppressive drugs, and the level of recommendation for further research in occurrence of CRC

 A

Evidence from one or more well-designed clinical study, and a clear mechanistic rationale supported by at least one in vitro or ex vivo functional study

 B

Evidence from ≥2 clinical studies with consistent data, and clear mechanistic rationale supported by in silico prediction (no in vitro functional study)

 C

Evidence from ≥2 clinical studies with consistent data but unclear or no mechanistic basis

 D

Conflicting data and convincing data against a functional effect

 1

Highly recommended candidate: QOE of grade A or B, and ≥1 positive association study in CRC risk factor or candidate not yet studied in CRC with a QOE of grade A

 2

Recommended candidate: candidate not yet studied in CRC risk factor with a QOE of grade B

 3

Potential candidate: QOE of C or candidate with a QOE of grade A or B unsuccessfully tested in one CRC risk factor (≤2 negative studies)

 4

Candidate to exclude: QOE of grade D or a QOE of grade A, B or C with convincing data against any statistical association in CRC risk factor (>2 negative studies)