Table S1.
Newcastle–Ottawa quality assessment scale
| Selection |
| 1) Representativeness of the exposed cohort |
| a) Truly representative of the average HCC patients in the community |
| b) Somewhat representative of the average HCC patients in the community |
| c) Selected group of users (eg, nurses, volunteers) |
| d) No description of the derivation of the cohort |
| 2) Selection of the nonexposed cohort |
| a) Drawn from the same community as the exposed cohort |
| b) Drawn from a different source |
| c) No description of the derivation of the nonexposed cohort |
| 3) Ascertainment of exposure (proof of HCC and Notch-1 measurement) |
| a) Secure record (eg, surgical records) |
| b) Structured interview |
| c) Written self-report |
| d) No description |
| 4) Demonstration that outcome of interest was not present at start of study |
| a) Yes |
| b) No |
| Comparability |
| 1) Comparability of cohorts on the basis of the design or analysis |
| a) Study controls for recurrence or metastasis |
| b) Study controls for any additional factor (age, sex, grade, tumor number, etc) |
| Outcome |
| 1) Assessment of outcome |
| a) Independent blind assessment |
| b) Record linkage |
| c) Self-report |
| d) No description |
| 2) Was follow-up long enough for outcomes to occur |
| a) Yes (3 years) |
| b) No |
| 3) Adequacy of follow-up of cohorts |
| a) Complete follow-up – all subjects accounted for |
| b) Subjects lost to follow-up unlikely to introduce bias – small number lost – >25% follow-up, or description provided of those lost |
| c) Follow-up rate <75% and no description of those lost |
| d) No statement |
Notes: A study can be awarded a maximum of one star for each numbered item within the Selection and Outcome categories. A maximum of two stars can be given for Comparability.
Abbreviation: HCC, hepatocellular carcinoma.