C-erbB-2 expression and its relationship with ploidy, p53 abnormalities and epidermal growth factor receptor content in human non-small cell lung cancer.

This study attempts to clarify the role of c-erbB-2 overexpression in human non-small cell lung cancer (NSCLC) and relate it with the p53 alterations, DNA index (D.I.) and epidermal growth factor receptor (EGFR) content in sixty four patients with NSCLC. c-erbB-2 and EGFR quantification were carried out from tissue homogenates using quantitative ELISA procedures. p53 alterations were determined by immunohistochemical (IHC) detection with the monoclonal antibody DO-7 and analysis for p53 mutations on exons 4 to 8 by single strand conformation polymorphism (SSCP). The D.I. was performed by flow cytometry. c-erbB-2 hyperexpression was found in 13 of 58 LC (22%), and it was closely associated with hyperdiploid tumors (D.I. >1.3; P = 0.00). The p53 abnormalities detected by SSCP were statistically more frequent in hyperdiploid tumors (16/25; P = 0.015) than in diploid ones (8/30). No relationship between the results of IHC p53 and SSCP was found. The patients with c-erbB-2 hyperexpressing tumors were prone to have frequent relapses (P = 0.03), although the patients with hyperdiploid NSCLC are the ones with the highest relapse rate (P = 0.008). From the results obtained in this study the following conclusions can be drawn: (a) c-erbB-2 hyperexpressing NSCLC are associated with abnormalities in other biological markers and with a greater rate of relapses; (b) SSCP seemed to be more specific that IHC to detect p53 molecular abnormalities; and (c) the D.I. is the parameter more tightly related with relapse.

Relationship of p53 molecular abnormalities with flow cytometry and growth factor receptor content in lung cancer.

This study attempts of clarify the oncological significance of the p53 molecular abnormalities and p53 expression in lung cancer (LC) and their relationship with flow cytometry (FC) parameters and epidermal growth factor receptor (EGFR). The study includes 65 samples taken from both LC and normal lung (NL). The p53 molecular abnormalities of exons 4-8 were studied by single strand conformation polymorphisms (SSCP) and the loss of heterozygosity (LOH) of exon 4 by the Metzler method. P53 protein was detected by Western blot. EGFR was determined by a radioligand assay using [125I]EGF. The FC parameters S phase fraction (SPF), DNA index (D.I.), G1G0 and growth rate (G2M + SPF) were evaluated from cellular monosuspensions. The LC with SSCP p53 molecular abnormalities have a significantly higher EGFR content (P < 0.001), SPF (P < 0.007), D.I. (P < 0.017) and a lower proportion of G1G0 cells (P < 0.04) than LC with no molecular abnormalities. No relationship between p53 molecular abnormalities and tumor TN or evolutive events was found. Neither the relationship between the molecular results and p53 expression detected by Western blot nor that of the p53 expression detected by Western with FC parameters or EGFR could be shown. In NL the growth fraction cells decrease significantly (P < 0.05) with the intensity of p53 expression. The lack of biological functionality of p53 with molecular abnormalities seemed to relate to fast growing LC whereas p53 expression detected by Western seemed more related to the wild type of p53.

Minimal illegitimate levels of cytokeratin K19 expression in mononucleated blood cells detected by a reverse transcription PCR method (RT-PCR).

Cytokeratin K19 (CK19) expression was evaluated by a reverse transcription PCR method (RT-PCR) in the RNA obtained from peripheral blood stem cell collections (PBSC) from four patients with breast cancers (BC) and 34 mononucleated blood cell (MBC) negative controls (17 PBMC from normal subjects 12 PBSC from different types of leukaemias--M3, M4Eo, M2, etc.--and two from patients with Hodgkin's lymphoma; and three bone marrow (BM) collections). Two BC tissues were taken as positive controls. The method studied (Datta YH, Paul T, Adams PT, Drobyski WR. Sensitive detection of occult breast cancer by reverse transcription polymerase chain reaction. J Oncol 1994;12:475-8) is sensitive enough to allow the detection of CK19 transcripts in a 10(-6) dilution of cDNA reverse transcribed from 1 microgram of BC RNA, but CK19 transcripts were also detected in 64% of the RNA obtained from the MBC controls. However, the amplified product detected in the control samples represents the transcript of the CK19 gene as confirmed by the results of Mae III digestion. It should be pointed out that although the CK19 expression was detected, the levels of expression in PBMC were almost negligible for they disappeared at 1:5 cDNA dilution. Moreover, a direct relationship between the number of BC cells added to PBMC and the increasing dilution levels of the cDNA necessary to prevent CK19 expression was observed. This allows us to conclude that the cDNA dilutions make it possible to distinguish the false from the true positive samples and that, in addition, the cDNA dilutions inform about the degree of BC cell contamination.