Activation of KRAS oncogene has been implicated in colorectal carcinogenesis. 
KRAS mutations can be detected in more than 30% of all patients with colorectal 
cancer (CRC). Most recently, regimens that include anti-epidermal growth factor 
receptor (EGFR) targeted antibodies, cetuximab and panitumumab, for metastatic 
CRC have been developed. Several recent studies have shown that patients with 
KRAS mutations in codons 12 and 13 in metastatic CRC do not benefit from 
anti-EGFR therapy. With the aim to determine KRAS status as predictive 
biomarker, 7 known mutations ofKRAS gene in codons 12 or 13 on 44 CRC samples 
were tested. After DNA extraction from paraffin-embedded tumor tissue blocks, 
KRAS mutations were analysed using quantitative real-time PCR with 
internationally certified method, for the first time in Croatia. Mutations were 
detected in 12 tumor samples: five patients with Gly12Val (GGT>GTT), three with 
Gly12Asp (GGT>GAT), two patients with Gly13Asp (GGC>GAC), one patient with 
Gly12Ser (GGT>AGT) and one with Gly12Cys (GGT>TGT) mutation in tumor. Our data 
about KRAS mutational status in the sample of Croatian population diagnosed with 
CRC have shown that incidence of KRAS mutation is 27%, which is consistent with 
results already reported worldwide. The final result must be a proper selection 
of the correct therapy with EGFR inhibitors for the patients with CRC which is 
critical for improving clinical outcomes, unnecessary toxicities, side effects 
and financial cost.