Nuclear DNA content of human breast carcinoma: a comparison of results obtained by microspectrophotometry and flow cytometry of paraffin embedded tissue.

This study compares 2 techniques for estimating the nuclear DNA content of tumor cell lines: (i) static cytometry of smears taken from fresh tissue and (ii) flow cytometry of cells extracted from paraffin embedded tissue. Parallel determinations of DNA content, using both techniques, were made on samples of tissue taken from 130 female patients with breast carcinoma. Using a simple classification into diploid and non-diploid groups, the 2 techniques yielded discrepant results in 11% of cases.

The nuclear DNA content of human breast carcinoma. Associations with clinical stage, axillary lymph node status, estrogen receptor status and outcome.

Using Feulgen-DNA cytophotometry, the nuclear DNA content was determined in specimens from 169 female patients with unilateral primary carcinoma of the breast. The tumors were classified as either diploid (73 cases: 43%) or hyperdiploid (96 cases), according to the ploidy of the tumor cells. Statistically significant associations were found between the DNA content and other characteristics of the patients and their tumors.

Nuclear DNA content and prognosis in human breast cancer: a static cytophotometric study.

Nuclear DNA content was measured by static cytophotometry in smears from breast carcinomas from 80 women, and the results were correlated with other prognostic variables and survival using multivariate statistical analysis. 49% of patients had diploid tumors and 51% hyperdiploid tumors. There was a strong correlation between DNA ploidy and axillary lymph node status, tumor size, ER status, and short term survival (median follow-up 40 months).

Feulgen DNA cytophotometry in histologic sections of mammary neoplasms.

Because of a lack of suitable archival material, it is rarely possible to make retrospective studies of the correlation between the prognosis for a patient with mammary carcinoma and the distribution of nuclear DNA in the cells of the neoplasm. An investigation of the possibility of using sections cut from paraffin-embedded specimens showed that such sections are not suitable for use in retrospective studies of breast carcinoma. Because of such factors as the heterogeneity in size and shape of the nuclei from neoplastic cells and their tendency to mold around each other, determinations of DNA content of cells in sections were extremely difficult; in this particular carcinoma it was found that the distribution of nuclear DNA as obtained from a Feulgen-stained histologic section was not the same as that obtained from a Feulgen-stained imprint smear, and some polyploid tumors were erroneously classified as aneuploid.

The second international standard for tetracycline.

A second international standard has been established to replace the first International Standard for Tetracycline, stocks of which were depleted. The International Unit of tetracycline is defined as the activity contained in 0.00101833 mg of the second International Standard, corresponding to a potency of 982 IU/mg.

The second international reference preparation of lymecycline.

The second International Reference Preparation of Lymecycline was established. Nine laboratories in 8 countries collaborated in assaying its potency in terms of the first International Reference Preparation, of which stocks had become exhausted. The best estimate of potency was taken to be 948 IU/mg, which was the unweighted geometric mean of a total of 124 assays.