Plasma DNA, microsatellite alterations, and p53 tumor mutations are associated with disease-free survival in radically resected non-small cell lung cancer patients: a study of the perugia multidisciplinary team for thoracic oncology.
BACKGROUND
This prospective study examined association between circulating plasma DNA, microsatellite alterations (MA), p53 mutations with time to relapse and survival in surgically treated non-small cell lung cancer (NSCLC) patients (pts).


METHODS
Plasma samples, adjacent lung tissue, and lung tumor tissue specimens were collected from consecutive patients with stage I-III NSCLC. Blood samples of 66 matched healthy donors with positive smoking history were collected as controls. The plasma DNA amount was determined by real-time PCR. The analysis of MA at loci D3S1300, D3S1289, D3S1266, and D3S2338 on chromosome 3p was performed by radiolabeled PCR. p53 Mutations (exons 5, 6, 7, and 8) were detected by PCR-single-strand conformational polymorphism assay.


RESULTS
There were 76 patients, 65 men; median age was 68 years (range, 42-86), 20 had stage I, 40 stage II, and 16 stage III, the majority of pts (48.7%) had squamous-cell histology. Sixty-nine (91%) were smokers and most had good Eastern Cooperative Oncology Group performance status (0/1:72/4). Mean circulating DNA of all pts was 60 ng/ml versus 5 ng/ml in smoker-matched controls (p < 0.0001). In pts without recurrence, mean circulating DNA was 48.5 ng/ml at baseline, 32.8 ng/ml at 3 month, and 20.6 ng/ml at 12 month after surgery. In pts with recurrence, mean circulating DNA at baseline was 97.1 ng/ml. At 3 month after surgery, mean DNA concentration was significantly lower in disease-free pts than in patients with recurrent disease (32.8 versus 292.7 ng/ml; p = 0.0016). MA in at least one locus was found in 39.5% of NSCLC tumors. p53 Genomic mutations were observed in 54.0% of tumor samples. Statistically significant associations were observed between MA and squamous-cell histotype (p = 0.007) and between p53 mutations and lymph node involvement (p = 0.012). MA and p53 mutations were found to be significantly associated with recurrence of disease (p = 0.033 and 0.026, respectively).


CONCLUSIONS
Our results suggest that MA and p53 mutations in tumor DNA have a potential prognostic role for disease recurrence in NSCLC patients, and elevated levels of plasma circulating DNA identify patients with possible systemic disease at diagnosis. This might be proposed as an early detection test of disease recurrence.
Ludovini
Vienna
V
Medical Oncology Division, Azienda Ospedale Perugia, Via Brunamonti 51, 06122 Perugia, Italy. oncolab@hotmail.com
Pistola
Lorenza
L
Gregorc
Vanesa
V
Floriani
Irene
I
Rulli
Eliana
E
Piattoni
Simonetta
S
Di Carlo
Luciana
L
Semeraro
Antonia
A
Darwish
Samir
S
Tofanetti
Francesca Romana
FR
Stocchi
Lucia
L
Mihaylova
Zhasmina
Z
Bellezza
Guido
G
Del Sordo
Rachele
R
Daddi
Giuliano
G
Crinò
Lucio
L
Tonato
Maurizio
M
D000230:Adenocarcinoma / Q000235:genetics / Q000556:secondary / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018287:Carcinoma, Large Cell / Q000235:genetics / Q000556:secondary / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000556:secondary / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000556:secondary / Q000601:surgery; D016022:Case-Control Studies; D004247:DNA / Q000097:blood* / Q000235:genetics; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000473:pathology / Q000601:surgery; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism
D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D004247:DNA