## Table 10 |
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Distribution of shortest path lengths from drug targets to the nearest disease protein |
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Distance |
Description |
Full PIN |
BioGRID |
Rual-Stelzl |
Rual-only |

0 | Drug targets = DPs | 436 | 319 | 71 | 25 |

1 | Drug targets interact with DPs | 619 | 246 | 47 | 10 |

2 | Drug targets and DPs have a common interactor | 154 | 163 | 77 | 25 |

3 | 3-step paths | 12 | 16 | 20 | 11 |

4 | 4-step paths | 1 | 1 | 1 | 2 |

5 | 5-step paths | - | 1 | - | - |

Inf | Drug targets disconnected from DPs | 5 | 5 | 5 | 1 |

The full PIN contains only 436 drug targets which, at the same time, are DPs. 619 different drug targets have a shortest path of “1” to the nearest DP (they interact), while 154 have a shortest path of “2” and 5 drug targets are disconnected from any disease target, probably due to missing interaction information. Smaller subsets show that, in general, drug targets do not get farther from disease proteins after data sub-setting, and, as a rule of thumb, there will always be a disease protein at least 4 steps away from any drug target. However, the proportion of drug targets in disconnected components is higher for subsets than it is for the full PIN.

Mora and Donaldson

Mora and Donaldson *BMC Bioinformatics* 2012 **13**:294 doi:10.1186/1471-2105-13-294