High concordance of KRAS status between primary colorectal tumors and related metastatic sites: implications for clinical practice.
OBJECTIVE
Several studies have suggested that KRAS somatic mutations may predict resistance to cetuximab- and panitumumab-based treatments in metastatic colorectal cancer (CRC) patients. Nevertheless, most experiences were conducted on samples from primaries. The aim of this study was to evaluate the grade of concordance in terms of KRAS status between primaries and related metastases.


METHODS
We analyzed KRAS codon 12 and 13 mutations from formalin-fixed sections of 107 CRC primaries and related metastases. Eight pairs were excluded from the analysis because of the low amount of tumor tissue in the available samples. The main characteristics were: 50 men, 49 women; median age at diagnosis, 71 years (range, 41-84). The metastatic sites analyzed were the liver in 80 patients (80.8%), lung in seven patients (7.1%), and other sites in 12 patients (12.1%).


RESULTS
A KRAS mutation was found in 38 (38.4%) primary tumors and in 36 (36.4%) related metastases. The rate of concordance was 96.0% (95% confidence interval, 90.0%-98.9%). Discordance was observed in only four (4%) patients.


CONCLUSIONS
Our results indicate that the detection of KRAS mutations in either primary or metastatic tumors from patients with CRC is concordant and this assessment could be used to predict response to targeted therapies such as cetuximab and panitumumab.
Santini
Daniele
D
Department of Oncology, University Campus Bio-Medico, Rome, Italy. d.santini@unicampus.it
Loupakis
Fotios
F
Vincenzi
Bruno
B
Floriani
Irene
I
Stasi
Irene
I
Canestrari
Emanuele
E
Rulli
Eliana
E
Maltese
Paolo Enrico
PE
Andreoni
Francesca
F
Masi
Gianluca
G
Graziano
Francesco
F
Baldi
Giacomo Giulio
GG
Salvatore
Lisa
L
Russo
Antonio
A
Perrone
Giuseppe
G
Tommasino
Maria Rosa
MR
Magnani
Mauro
M
Falcone
Alfredo
A
Tonini
Giuseppe
G
Ruzzo
Annamaria
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors; D005260:Female; D011905:Genes, ras; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009362:Neoplasm Metastasis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D012189:Retrospective Studies; D018631:ras Proteins / Q000235:genetics*
C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins