Synthesis of cDNA Fort he synthesis of c DNA (complementary deoxyribonucleic acid) the amount of RNA used was 2µg for a final volume of 20 µg. The RNA was mixed with 1 µl oligonucleotide 12-18 (INVITROGEN, Carlsbad, CA) and 1 µl de dNTPs (deoxynucleoside triphosphate) 10mM (Applied Biosystems, Roche). After the addition of 4 µl of Buffer 5 X (Tris- HCl (hydrochloric acid) 250mM, KCl (potassium chloride) 375 mM MgCl2 15mM), 2 µl de DTT (dithiothreitol) (0.1M) and wáter, all the mix was incubated at at 37° for two minutes and 1 µl of MMLV(Moloney Murine Leukemia Virus Reverse Transcriptase) Reverse transcriptase- enzyme (200u) (INVITROGEN, Carlsbad, CA) and incubated at 37°C for 50 minutes.