Albert A. Keshgegian

P-cadherin expression in breast carcinoma indicates poor survival.

The cadherin family of cell‐cell adhesion molecules and their associated proteins, the catenins, are essential to embryonic development and the maintenance of adult tissues. During development, the homotypic interaction of a particular cadherin with an identical cadherin expressed on a neighboring cell results in the sorting of cells to form distinctive tissues. Cadherins are believed to be tumor suppressors, and their altered expression and function have been associated with tumor development.

Comparison of transcription of chromatin by claf thymus and E. coli RNA polymerases

Abstract Kinetic parameters of transcription of DNA and chromatin by calf thymus and E. coli RNA polymerases were studied. Using calf thymus RNA polymerase, the theoretical maximum velocity (Vmax) for chromatin is similar to that for DNA. The concentration of chromatin required to reach one-half the maximum velocity (Km) is greater than the Km for DNA. Using E. coli RNA polymerase, the Km for chromatin is similar to the Km for DNA, whereas the Vmax for chromatin is much less than the Vmax for DNA. These differences suggest that calf thymus RNA polymerase binds to specific, selected sites on chromatin and transcribes at all of these sites. E. coli RNA polymerase binds to many non-selected sites and transcribes at some or all of them.

Estrogen receptor protein in malignant carcinoid tumor a report of 2 cases

Two cases of metastatic malignant carcinoid tumor in elderly women contained significant amounts of estrogen receptor (19 and 32 femtomoles/mg protein) as shown by Scatchard‐plot analysis of a dextran‐coated charcoal assay, inhibition of binding by an estrogen analog (67 and 63%) and high‐affinity binding (Kd = 6.8 and 2.6 × 10−10 M). The demonstration of estrogen receptor in malignant carcinoid tumor expands the spectrum of non‐breast or non‐gynecologic neoplasms that contain the receptor. The significance of estrogen receptor in such tumors is uncertain; it may represent aberrant derepression of the gene for estrogen receptor protein in a malignant tumor.

Immunofixation as an adjunct to immunoelectrophoresis in characterization of serum monoclonal immunoglobulins

We evaluated quantitatively the usefulness of immunofixation (IF) as an adjunct to immunoelectrophoresis (IEP) in characterizing serum monoclonal proteins. In 33 out of 97 consecutive patients with one or more homogeneous bands on cellulose acetate serum protein electrophoresis, a monoclonal immunoglobulin could not be characterized with certainty by IEP. Of these 33 cases, in 76% a monoclonal immunoglobulin was subsequently characterized by IF on agarose gel. In 18% IF provided additional suggestive information, and in 6% it provided no additional or less information than IEP. The mean concentration of monoclonal proteins (other than free light chains) that could be characterized by IEP was 25 g/l. The monoclonal proteins that required IF for characterization were all less than 10 g/l. Of all monoclonal proteins below 10 g/l, 53% required IF for complete characterization. IF is a useful adjunct to IEP, primarily in cases where the concentration of monoclonal immunoglobulin is less than 10 g/l.

Transcription of chromatin by an RNA polymerase of calf thymus which is sensitive to high concentrations of α-amanitin

Abstract RNA polymerase which is sensitive to high concentrations of α-amanitin has been obtained by low-salt extraction of whole calf thymus tissue. Some characteristics of this Form III-type polymerase have been compared with Form II. Both enzymes require a higher concentration of purine nucleoside triphosphates compared to pyrimidine nucleoside triphosphates. The Form III-type polymerase is larger than Form II. It transcribes native DNA better than denatured DNA and transcribes chromatin efficiently. Under various salt and metal conditions Form II transcribes native DNA and chromatin poorly relative to denatured DNA. These results suggest that Form III RNA polymerase is a useful enzyme with which to study the transcription of chromatin in vitro and may possess some factor (which Form II lacks) which is necessary for transcription of double-stranded templates.

Influence of surgical technique on estrogen and progesterone receptor determinations in breast cancer

The effect of surgical technique on hormone receptor values in breast cancer tissue was examined. One hundred and thirty‐one women with breast cancer were divided into three groups: Group I, definitive diagnosis at frozen section and tissue taken for receptor determination; Groups II and III, diagnosis made by aspiration biopsy cytology, with tissue obtained from modified radical mastectomy in Group II and tissue obtained from mastectomy performed separately, prior to axillary lymph node dissection, in Group III. The rates of estrogen and progesterone receptor positivity, and the mean levels of receptor, did not differ significantly among the three groups. Thus tumor tissue from a mastectomy specimen can be reliably used for hormone receptor determinations, if the tumor tissue is kept cold and rapidly frozen for storage. Women whose cancer has been diagnosed by aspiration biopsy cytology need not undergo an additional open biopsy solely to obtain tissue for receptor determinations.

Suppression of one monoclonal immunoglobulin in the presence of another in multiple myeloma: Evidence for benign B‐cell neoplasia

The case of a 77‐year‐old man with two monoclonal proteins, IgG lambda and IgG kappa, is presented. The IgG kappa protein increased in concentration, and, after two years, overt multiple myeloma developed with anemia and suppression of polyclonal immunoglobulins. The IgG lambda protein at first remained constant, but disappeared when overt myeloma developed. The disappearance of the IgG lambda protein suggests suppression of one neoplastic immunoglobulin clone by another, more aggressive, clone. This indicates that idiopathic monoclonal gammopathy can result from a benign neoplasm of B‐cells that is responsive to regulatory factors and is not an early stage of myeloma.

No relationship between lactate dehydrogenase and estrogen receptor levels in clinical human breast cancer

The level of lactate dehydrogenase has been reported to increase in a human breast cancer cell line as a result of estrogen action [4]. This finding suggests that lactate dehydrogenase may be useful in clinical human breast cancer as a marker for intactness of the estrogen receptor pathway and for probability of response to hormonal therapy. In 97 hunan breast cancer specimens submitted for estrogen receptor analysis, the level of lactate dehydrogenase varied from 0.19 to 3.3 I.U. per mg of extractable protein and bore no relation with either the presence of estrogen receptor or its level. It thus appears that lactate dehydrogenase is not a useful marker for endocrine responsiveness in clinical breast tumors.