The mutation of STK11 has been regcognized to be the major cause of Peutz-Jeghers syndrome (PJS).The aim of this study was to confirm the mutation rate of gene associated with gastrointestinal malignancies,including STK11, APC,PMS1,et al. Furtherly, the investigators analyze the association of STK11 with gut microbiota.

All patients diagnosed as PJS were enrolled and accepted second generation gene sequencing with their blood specimens. Then all patients allocated into gene mutation group and no gene mutation group according to if the cases accompany with gene mutation of STK11.Also, health persons were enrolled and a case controlled study will be carried out.All patients and health persons accepted 16s rRNA sequencing with their feces specimens.

Inclusion Criteria:

1. Subject with ages from 18-70 years old.
2. Subject diagnosed with Peutz-Jeughers syndrome.
3. Subject without hypertension, diabetes and other gastrointestinal diseases.
4. The consent form has been signed.

Exclusion Criteria:

1. Subject is younger than 18 years or older than 70 years.
2. Subject with hypertension,diabetes and other gastrointestinal diseases.
3. Subject taken or adminstered medicine associated with digestive function during latest 1 month.
4. Pregnant women.