SMAD2 and colorectal neoplasm: In particular, D18S51 (18q21.33), FGA (4q31.3), and SE33(6q14) are near some regions which frequently undergo deletions in gastrointestinal tumors such as 5q22.2 (APC gene), 17p13.1 (TP53 gene), 18q (DCC, SMAD2 and 4, cables) [21], 4q28.3 (protocadherin 10) [22], and different portions of the six chromosomes associated with genes mutated in colorectal tumors.