Prognostic value of flow cytometric DNA analysis in non-small-cell lung cancer: rationale of sequential processing of frozen and paraffin-embedded tissue

Prognostic value of DNA ploidy: 5-year follow-up of patients with resectable squamous cell carcinoma (SCC) of the lung

This study was designed to show the relation between DNA-ploidy in patients with resectable lung cancers and their 5-year survival rate. The results are compared with those from our 2-year follow-up study of the same group of patients published in 2000. The group of 80 patients with SCC who underwent lung resection between 1995 and 96 were re-analyzed. For the statistical analysis the hazard Cox model and an exponential multiple regression model were used. The survival curves were drawn using the Kaplan-Meier method. DNA-aneuploidy was found in 45% of cancer tumors. There was no statistically significant correlation between aneuploidy and gender, age, cancer staging or grading. In the 3-year follow-up the survival rate in patients with aneuploid type tumors was significantly lower than in those with the diploid type. However, this difference was not found after 5 years of follow-up. Tumor ploidy was an independent prognostic factor only in patients between 55 and 60 years of age. The mortality rate in patients with aneuploid tumors was mainly the result of distant metastases while, in patients with diploid tumors, local recurrence was the main reason for death. In the first three years after surgical resection patients with aneuploid tumors are at higher risk of distant metastases than patients with the diploid type. Tumor ploidy can be recognized as an independent prognostic factor in younger (55-60) patients. Aneuploidy promoted the occurrence of early distant metastases while the diploid type was associated with late (after 3 years) local tumor recurrence.

The Prospect of Biologic Staging of Non–Small-Cell Lung Cancer

The reductionistic approach to cancer research has led to an enormous amount of information and publications regarding the molecular biologic processes that take place in cancer tissue. However, the specific influence of this information on clinical practice has been limited. With the advent of new reductionistic tools like the transcriptomic and proteomic technologies, many would argue that further advances in the field of lung cancer research will be dominated by advances on the technical level. However, we anticipate that the most revolutionary advances will be those at a conceptual level. Medical science has always been reductionistic in essence, reducing and analyzing the composing elements of our complex biologic machinery, overlooking the fact that the interrelation among a set of simple determinants creates a new dimension of characteristics and functions. Problems emerging from a reductionistic approach are heterogeneity and variability. This review addresses the current conceptual problems in the field of lung cancer biology and provides a new conceptual model based on recent publications.

Stratification of the biologic aggressiveness of non-small cell lung cancer using DNA flow cytometry and immunohistochemistry for the retinoblastoma protein

DNA ploidy pattern and S-phase fraction (SPF) measured by flow cytometry and expression of the retinoblastoma gene product (pRB) estimated by immunohistochemistry were correlated with outcome in 114 patients who received a curative operation for primary non-small cell lung cancer (NSCLC). One hundred ten tumors yielded an adequate DNA histogram, and all tumors exhibited an assessable immunohistochemical stain. DNA diploidy was detected in 31 tumors and DNA aneuploidy in 79 tumors. The mean SPF was 14.1 +/- 6.4%. Eighty tumors were positively stained, and 34 tumors were negative for pRB. Multivariate analysis clarified that both TNM staging and DNA ploidy were prognostic factors after surgery. In 39 recurrent cases, the SPF value was inversely correlated with disease-free interval. With only supportive care after recurrence, high SPF tumors and pRB-negative tumors progressed rapidly, whereas active treatment yielded an equivalent effect on recurrent tumors regardless of the SPF or pRB expression. DNA ploidy is related to the risk of recurrence, while SPF is related to tumor growth rate and the impact of active treatment on recurrence. The utility of pRB expression was limited. The combination of DNA ploidy and SPF allows practical stratification of the biologic aggressiveness of NSCLC.

Prognostic factors in non-small cell lung cancer: a decade of progress

STUDY OBJECTIVES

To provide a systematic overview of the literature investigating patient and tumor factors that are predictive of survival for patients with non-small cell lung cancer (NSCLC), and to analyze patterns in the design of these studies in order to highlight problematic aspects of their design and to advocate for appropriate directions of future studies.

DESIGN

A systematic search of the MEDLINE database and a synthesis of the identified literature.

MEASUREMENTS AND RESULTS

The database search (January 1990 to July 2001) was carried out combining the MeSH terms prognosis and carcinoma, nonsmall cell lung. Eight hundred eighty-seven articles met the search criteria. These studies identified 169 prognostic factors relating either to the tumor or the host. One hundred seventy-six studies reported multivariate analyses. Concerning 153 studies reporting a multivariate analysis of prognostic factors in patients with early-stage NSCLC, the median number of patients enrolled per study was 120 (range, 31 to 1,281 patients). The median number of factors reported to be significant in univariate analyses was 4 (range, 2 to 14 factors). The median number of factors reported to be significant in multivariate analyses per study was 2 (range, 0 to 6 factors). The median number of studies examining each prognostic factor was 1 (range, 1 to 105 studies). Only 6% of studies addressed clinical outcomes other than patient survival.

CONCLUSIONS

While the breadth of prognostic factors studied in the literature is extensive, the scope of factors evaluated in individual studies is inappropriately narrow. Individual studies are typically statistically underpowered and are remarkably heterogeneous with regard to their conclusions. Larger studies with clinically relevant modeling are required to address the usefulness of newly available prognostic factors in defining the management of patients with NSCLC.

Ability of bivariate cytokeratin and deoxyribonucleic acid flow cytometry to determine the biologic aggressiveness of resectable non-small cell lung cancer

OBJECTIVE

The purpose of this study was to clarify the significance of bivariate cytokeratin and DNA flow cytometry for analysis of the biologic aggressiveness of resectable non-small cell lung cancer.

METHODS

In 92 patients who underwent curative operations, the DNA ploidy status and S-phase fractions of the cancer cell populations inside the tumors were analyzed by a cytokeratin gating technique with paraffin-embedded specimens and were correlated with the surgical results.

RESULTS

Ninety tumors yielded assessable DNA histograms. DNA diploidy was detected in 25 tumors with a mean S-phase fraction of 14.3% +/- 4.7%, and DNA aneuploidy was detected in 65 tumors with a mean S-phase fraction of 15.1% +/- 7.1%. The 5-year overall and recurrence-free survivals were 73.3% and 70.3%, respectively. Multivariate analysis showed that only TNM staging was a prognostic factor after surgery. There was a negative correlation between the logarithms of S-phase fraction and the disease-free interval for 22 patients with proven recurrence (P =.006). The tumors with high S-phase fractions recurred more rapidly than did those with low S-phase fractions.

CONCLUSION

In a bivariate analysis of cytokeratin and DNA flow cytometry in resectable non-small cell lung cancer, the S-phase fraction appeared to be correlated with the disease-free interval. However, DNA ploidy and S-phase fraction were not predictive of either recurrence or survival after operation. Thus DNA flow cytometry may be of limited use for the analysis of the biologic aggressiveness of lung cancer.

Aneuploidy and prognosis of non-small-cell lung cancer: a meta-analysis of published data

In lung cancer, DNA content abnormalities have been described as a heterogeneous spectrum of impaired tumour cell DNA histogram patterns. They are merged into the common term of aneuploidy and probably reflect a high genotypic instability. In non-small-cell lung cancer, the negative effect of aneuploidy has been a subject of controversy inasmuch as studies aimed at determining the survival-DNA content relationship have reported conflicting results. We made a meta-analysis of published studies aimed at determining the prognostic effect of aneuploidy in surgically resected non-small-cell lung cancer. 35 trials have been identified in the literature. A comprehensive collection of data has been constructed taking into account the following parameters: quality of specimen, DNA content assessment method, aneuploidy definition, histology and stage grouping, quality of surgical resection and demographic characteristics of the analysed population. Among the 4033 assessable patients, 2626 suffered from non-small-cell lung cancer with aneuploid DNA content (overall frequency of aneuploidy: 0.65; 95% CI: (0.64-0.67)). The DerSimonian and Laird method was used to estimate the size effects and the Peto and Yusuf method was used in order to generate the odds ratios (OR) of reduction in risk of death for patients affected by a nearly diploid (non-aneuploid) non-small-cell lung cancer. Survivals following surgical resection, from 1 to 5 years, were chosen as the end-points of our meta-analysis. Patients suffering from a nearly diploid tumour benefited from a significant reduction in risk of death at 1, 2, 3 and 4 years with respective OR: 0.51, 0.51, 0.45 and 0.67 (P< 10(-4)for each end-point). 5 years after resection, the reduction of death was of lesser magnitude: OR: 0.87 (P = 0.08). The test for overall statistical heterogeneity was conventionally significant (P< 0.01) for all 5 end-points, however. None of the recorded characteristics of the studies could explain this phenomenon precluding a subset analysis. Therefore, the DerSimonian and Laird method was applied inasmuch as this method allows a correction for heterogeneity. This method demonstrated an increase in survival at 1, 2, 3, 4 and 5 years for patients with diploid tumours with respective size effects of 0.11, 0.15, 0.20, 0.20 and 0.21 (value taking into account the correction for heterogeneity;P< 10(-4)for each end-point). Patients who benefit from a surgical resection for non-small-cell lung cancer with aneuploid DNA content prove to have a higher risk of death. This negative prognostic factor decreases the probability of survival by 11% at one year, a negative effect deteriorating up to 21% at 5 years following surgery.

Prognostic significance of DNA ploidy in squamous cell lung carcinoma: is it really worth it?

BACKGROUND

Many previous studies attempted to associate DNA quantification with prognosis for lung cancer, but there is a divergence of opinion about its value. The purpose of the study was to evaluate the frequency of abnormal DNA content in squamous cell cancer (SCC) and analyze its correlation with late survival rates after surgical treatment.

METHODS

A group of 110 patients surgically treated because of SCC was analyzed. Paraffin-embedded pathologic material underwent cytometric analysis. Postoperative follow-up was performed with standard follow-up visits. The statistical analysis was carried out using Mann-Whitney's U and chi2 tests to compare various variables in both groups. The survival curves were drawn using the Kaplan-Meier method. Clinical staging, regional metastasis, and ploidy, were analyzed with multivariate analysis for having a great impact on survival rates.

RESULTS

Fifty (45%) tumors were DNA aneuploid. The survival rate in patients with aneuploid cancers was worse than in those with diploid tumors and the most frequent cause of death was local recurrence (p < 0.05).

CONCLUSIONS

DNA content abnormalities were found to be an important prognostic factor in patients with SCC. The DNA quantification can select a group of high risk of recurrence even after a radical procedure and set new guidelines for adjuvant therapy.

The prognostic value of DNA content analysis in patients with squamous cell lung cancer treated surgically

The aims of the study were to assess the degree of ploidy and determine whether it had any influence on the remission time and survival of surgically treated patients with squamous cell lung cancer. The results were then related to the clinical staging, grading, size and location of the tumor. Tissue samples of squamous cell lung carcinoma (n=80) resected between 1995 and 1996 in the Department of Thoracic Surgery at University of Medical Sciences in Poznan were prepared using the modified Hedley's method. The measurements were made by means of a Cytoron Absolute flow cytometer. Abnormal (aneuploid) DNA was found in 45% of the tumors. In the 2-year observation period significantly more patients with aneuploid tumors died (75%) than those with diploid tumors (43.2%), P<0.05. No significant correlation was found between the ploidy and frequency of metastasis to regional lymph nodes, tumor size, location or grading. Estimation of the DNA content in cancer cells appears to be a significant prognostic factor. Furthermore measurement of the DNA content can be useful after surgery to estimate the risk of recurrence.

Prognostic value of the quantified expression of p185 in non-small cell lung cancer

BACKGROUND

We sought to assess the relationship between tissue concentration of erb -b-2 or neu oncogene-encoded protein (p185(neu)) with overall survival in patients with non-small cell lung cancer.

METHODS

Levels of protein p185(neu) were determined in 102 patients with the diagnosis of non-small cell lung cancer. Concentration of p185(neu) protein was determined by using enzyme immunoassay and evaluated by using several variables. The relative prognostic importance of this marker and its influence on other prognostic factors was evaluated by using the Cox regression model.

RESULTS

The mean p185(neu) value in these samples was 250 +/- 200 U/mg (95% confidence interval, 210-290). This distinguished two groups within the tumoral population: those with less than 350 U/mg and those with 350 U/mg or greater (80th percentile). Multivariable analysis established an independent prognostic value for protein p185(neu). Patients with p185(neu) values of the 80th percentile or greater had a risk of death that was 2.11-fold (95% confidence interval, 1.10-4.05) that of patients with values of less than 350 U/mg (P =.03), and increases in the neu oncogene of 100 U/mg increased the probability of death by 17% (P =.02; 95% confidence interval, 1.04-1.31).

CONCLUSION

This study shows that the p185(neu) expression is an objective and comparable variable for the assessment of phenotypic aggressivity in non-small cell lung cancer, and in the future, it could be included in daily clinical practice.

DNA aneuploidy, S-phase fraction and nuclear p53 positivity in non-small cell lung carcinoma

OBJECTIVES

Surgical resection currently offers the best option for managing non-small cell lung carcinoma (NSCLC) but its efficiency is limited by subsequent tumor recurrence. We evaluated whether flow cytometric study and the p53 gene staining pattern may be useful in this respect.

DESIGN AND METHODS

We took biopsy samples of 40 patients with operable NSCLC to study the frequency of aneuploidy, proliferative activity, and alterations in the p53 tumor suppressor gene and compared them with clinicopathological parameters such as age, gender, smoking, histological type, tumor size, and degree of differentiation. To study DNA content, the nuclei were analyzed by flow cytometry using a FACS flow cytometer (Becton-Dickinson) equipped with an argon ion laser, with a propidium iodide excitation of 488 nm. We used the immunohistochemical technique for p53 analysis in samples of paraffin-embedded tissue corresponding to the same patients from whom fresh tissue was taken.

RESULTS

Nuclear p53 staining was detected in 66.7% of the samples; 69.4% of the cases revealed aneuploid DNA histograms and 59% presented with an S phase fraction of more than 12%. Comparison with clinicopathological parameters showed that p53 protein was associated significantly with histological classification (p = 0.04), gender (p = 0.01), and smoking (p = 0.04).

CONCLUSIONS

Immunodetection of p53 overexpression and DNA ploidy in the bronchial epithelium may be a useful tool in any future multifactorial analysis in such tumors for identifying previous lesions that may progress to malignancy.