Tumor-associated glycoprotein expression in salivary gland mucoepidermoid carcinomas: an immunohistochemical study using the monoclonal antibody B72.3.

The monoclonal antibody B72.3 recognizes a mucin-like glycoprotein which is expressed in a variety of human malignancies including adenocarcinomas of the breast, colon, lung, endometrium, pancreas, and ovary. The antibody, an immunoglobulin G (IgG1) subclass monoclonal antibody, was generated from membrane-enriched fractions of metastatic mammary carcinoma. Because the antigen detected by B72.3 is expressed in a broad spectrum of human neoplasms, B72.3 is a potentially useful marker for glandular neoplasms. Despite its potential usefulness, there is only one previous comprehensive study which has examined the distribution of the tumor-associated glycoprotein (TAG-72), as detected by B72.3, in salivary neoplasms. We examined 21 mucoepidermoid carcinomas with the antibody. Twenty (95%) of the 21 carcinomas stained positively. The only carcinoma that did not stain was initially thought to be a high-grade mucoepidermoid carcinoma based on immunohistochemical staining. Further review, however, indicated that this lesion was most likely a pure squamous cell carcinoma, and the absence of TAG-72 antigen expression was helpful in this regard. Among those neoplasms which stained with B72.3, the strongest staining was seen in the low-grade carcinomas. These results suggest that B72.3 may be a useful marker for glandular differentiation in mucoepidermoid carcinomas.

The incidence of p53 mutations increases with progression of head and neck cancer.

To establish a genetic model of the progression of head and neck squamous carcinoma we have defined the incidence and timing of p53 mutations in this type of cancer. We sequenced the conserved regions of the p53 gene in 102 head and neck squamous carcinoma lesions. These included 65 primary invasive carcinomas and 37 noninvasive archival specimens consisting of 13 severe dysplasias and 24 carcinoma in situ lesions. The incidence of p53 mutations in noninvasive lesions was 19% (7/37) and increased to 43% (28/65) in invasive carcinomas. These data suggest that p53 mutations can precede invasion in primary head and neck cancer. Furthermore, the spectrum of codon hotspots is similar to that seen in squamous carcinoma of the lung and 64% of mutations are at G nucleotides, implicating carcinogens from tobacco smoke in the etiology of head and neck squamous carcinoma.

Recurrent meningitis and a congenital perilymph fistula.

In any child with recurrent meningitis, the presence of a congenital perilymph fistula must be entertained. All of the patients must have an audiologic assessment, and if a sensorineural loss is demonstrated, CT of the temporal bones should be performed. CT is excellent in identifying malformations within the temporal bones, fistulous tracts, soft tissue densities in the middle ear, and defects in the tegmen tympani. Although MRI may provide superior discrimination of the audiovestibular and facial nerves and cerebellopontine angle, presently it does not offer any distinct advantages over CT in evaluation of the inner ear. When a fistula is suspected, an exploratory tympanotomy is recommended, and any CSF leak is sealed with muscle.

DNA content of human squamous cell carcinoma cell lines. Analysis by flow cytometry and chromosome enumeration.

Fifteen squamous cell carcinoma cell lines derived from nine patients were examined for DNA content by flow cytometry and chromosome counts. Using human peripheral blood leukocytes and nucleated trout and chicken red blood cells as standards, the DNA indexes of the squamous cell carcinoma cell lines were found to range from 1.1 to 3.3. The DNA content was a stable characteristic of individual cell lines in multiple passages over a seven-month period. Although flow cytometry could detect abnormal DNA content even in diploid tumor lines, the chromosome number correlated well with the DNA content by flow cytometry. In cases in which more than one cell line was established from the same patient, the individual cell lines were found to differ in their DNA content. The cell lines established from metastatic or recurrent tumors usually had a lower DNA content and chromosome number and exhibited a more aggressive in vitro growth pattern than the primary tumor or earlier recurrence. We hypothesize that "streamlined" and aggressive cell populations may evolve in vivo from more slowly growing hyperploid precursor tumor cell populations when in the course of random loss of DNA or chromosomes those that confer no growth advantage are lost, while those that do confer growth advantage are retained.