Table 1 The datasets retrieved from GEO and ArrayExpress

3 human colorectal cancer derived from a primary tumor VS. 3 corresponding lymph node metastases

8 squamous cell carcinoma of the oral cavity VS. 19 corresponding lymph node metastases

15 head and neck squamous cell carcinoma VS. 3 corresponding lymph node metastases

12 head and neck squamous cell carcinoma VS. 11 corresponding lymph node metastases

2 human hepatocellular carcinoma under hypoxia for 2 hours VS. 2 control human hepatocellular carcinoma

2 human hepatocellular carcinoma under hypoxia for 24 hours VS. 2 control human hepatocellular carcinoma

22 squamous cell carcinoma of the oral cavity VS. 5 corresponding lymph node metastases

100 primary breast cancer VS. 21 lung metastases

7 primary prostate cancer VS. 6 metastases

2 human Burkitt's lymphoma under hypoxia VS. 2 control human Burkitt's lymphoma

13 primary medulloblastomas VS. 10 metastatic medulloblastomas

3 samples from normal melanocyte culture VS. 12 samples from culture of cutaneous metastasis of melanoma

3 samples from normal melanocyte culture VS. 12 samples from culture of cutaneous metastasis of melanoma

45 samples from culture of cutaneous melanoma metastasis

1 primary prostate carcinoma VS. 1 metastatic prostate carcinoma

65 primary prostate tumors VS. 25 metastatic prostate tumors

66 primary prostate tumors VS. 25 metastatic prostate tumors

65 primary prostate tumors VS. 25 metastatic prostate tumors

11 poorly metastatic melanoma VS. 21 highly metastatic melanoma

3 poorly metastatic prostate tumors VS. 3 highly metastatic prostate tumors

10 poorly metastatic melanoma VS. 29 highly metastatic melanoma

31 primary melanoma VS. 52 melanoma metastasis