Masaharu Kiyama

Correlation between the status of the p53 gene and survival in patients with stage I non-small cell lung carcinoma.

The association of p53 abnormalities with the prognosis of patients with non-small cell lung carcinoma (NSCLC) has been extensively investigated to date, however, this association is still controversial. Therefore, we investigated the prognostic significance of p53 mutations through exons 2 to 11 and p53 protein expression in 103 cases of stage I NSCLC. p53 mutations were detected in 49 of 103 (48%) tumors. Two separate mutations were detected in four tumors giving a total of 53 unique mutations in 49 tumors. Ten (19%) of mutations occurred outside exons 5 – 8. Positive immunohistochemical staining of p53 protein was detected in 41 of 103 (40%) tumors. The concordance rate between mutations and protein overexpression was only 69%. p53 mutations, but not expression, were significantly associated with a shortened survival of patients (P<0.001). Furthermore, we investigated the correlation between the types of p53 mutations and prognosis. p53 missense mutations rather than null mutations were associated with poor prognosis (P<0.001 in missense mutations and P=0.243 in null mutations). These results indicated that p53 mutations, in particular missense mutations, rather than p53 expression could be a useful molecular marker for the prognosis of patients with surgically resected stage I NSCLC.

Deoxyribonucleic acid concentration using acoustic radiation force

A deoxyribonucleic acid (DNA) concentration method using acoustic radiation force is proposed. Ethanol was added to an aqueous DNA sample in order to initiate clustering of the DNA molecules of 2686 bps. The change in the distribution of the DNA clusters induced by a standing wave ultrasound irradiation was observed with an optical microscope. The observable DNA clusters gathered on the pressure node in the ultrasonic standing wave field and formed larger clusters that did not break apart after the irradiation was stopped. Without ultrasound irradiation, no significant change in the cluster distribution was observed. This method may have a potential use for concentrating and collecting biomaterials such as nucleic acids and proteins.