Sebaceous carcinoma (SC) is a rare malignancy, affecting mainly the periocular glands. To the best of the authors’ knowledge, this is the first English-language report of parotid SC affecting children; two cases are presented. Immunohistochemical studies included 29 different antibodies (15 of these were cytokeratins, CKs). For each case, DNA ploidy status was determined using isolated nuclei stained with Feulgen and analysed using a DNA image cytometry system. Most of the tumour cells were positive for CKs AE1/AE3, 34B12, 5 and 7. The CK14 pattern depicted the monolayer of basal cells surrounding the islands of malignant tissue, while the more central sebaceous differentiated cells were negative. Epithelial membrane antigen was strongly positive in the well differentiated cells, while most of the basaloid peripheral cells were negative, and only a few cells were positive for carcinoembryonic antigen. β catenin, E cadherin and C-erb B2 were expressed by most of the cells including the more differentiated sebaceous cells. Tumour cells were negative for muscle or myoepithelial markers, androgen, oestrogen and progesterone receptors. Both SCs were uniformly diploid, and showed low proliferative indices for p53, Ki-67 and Mcm-2, which is consistent with the good clinical course presented by these patients so far.

Histopathological assessment of myxofibrosarcoma may be difficult, especially on the basis of a small core biopsy, which enables only a crude evaluation of grade and prognosis. We have tested the hypothesis that determination of cell cycle state may assist in the diagnostic assessment of myxofibrosarcoma. We have studied 51 cases of high-grade (n=20), intermediate-grade (n=21), and low-grade (n=10) myxofibrosarcomas, as well as nine cases of benign myxoma. Cell cycle state within tumors was determined by immunostaining for the recently described marker minichromosome maintenance protein 2 (MCM2), together with Ki67. Labelling indices for both markers were correlated with tumor grade, mitotic index, and time to first recurrence. The MCM2 labelling indices were significantly higher than the Ki-67 labelling indices. Both indices showed a significant correlation with the mitotic index and both showed significant increases with increasing grade of myxofibrosarcoma. The MCM2 labelling index (but not the Ki67 labelling index) showed a significant inverse exponential correlation with the time to first recurrence. Myxoid and cellular areas showed no difference in the MCM2 and Ki-67 labeling index, suggesting that clinically useful information could be obtained from any component of a myxofibrosarcoma sampled in a needle biopsy and/or cytological specimen. We therefore suggest that assessment of cell cycle state may be a useful diagnostic adjunct in the histopathological assessment of myxofibrosarcoma, by enabling more accurate determination of grade and prediction of outcome.

The productive cycle of human papillomaviruses (HPVs) can be divided into discrete phases. Cell proliferation and episomal maintenance in the lower epithelial layers are followed by genome amplification and the expression of capsid proteins. These events, which occur in all productive infections, can be distinguished by using antibodies to viral gene products or to surrogate markers of their expression. Here we have compared precancerous lesions caused by HPV type 16 (HPV16) with lesions caused by HPV types that are not generally associated with human cancer. These include HPV2 and HPV11, which are related to HPV16 (supergroup A), as well as HPV1 and HPV65, which are evolutionarily divergent (supergroups E and B). HPV16-induced low-grade squamous intraepithelial lesions (CIN1) are productive infections which resemble those caused by other HPV types. During progression to cancer, however, the activation of late events is delayed, and the thickness of the proliferative compartment is progressively increased. In many HPV16-induced high-grade squamous intraepithelial lesions (CIN3), late events are restricted to small areas close to the epithelial surface. Such heterogeneity in the organization of the productive cycle was seen only in lesions caused by HPV16 and was not apparent when lesions caused by other HPV types were compared. By contrast, the order in which events in the productive cycle were initiated was invariant and did not depend on the infecting HPV type or the severity of disease. The distribution of viral gene products in the infected cervix depends on the extent to which the virus can complete its productive cycle, which in turn reflects the severity of cervical neoplasia. It appears from our work that the presence of such proteins in cells at the epithelial surface allows the severity of the underlying disease to be predicted and that markers of viral gene expression may improve cervical screening.

The productive cycle of human papillomaviruses (HPVs) can be divided into discrete phases. Cell proliferation and episomal maintenance in the lower epithelial layers are followed by genome amplification and the expression of capsid proteins. These events, which occur in all productive infections, can be distinguished by using antibodies to viral gene products or to surrogate markers of their expression. Here we have compared precancerous lesions caused by HPV type 16 (HPV16) with lesions caused by HPV types that are not generally associated with human cancer. These include HPV2 and HPV11, which are related to HPV16 (supergroup A), as well as HPV1 and HPV65, which are evolutionarily divergent (supergroups E and B). HPV16-induced low-grade squamous intraepithelial lesions (CIN1) are productive infections which resemble those caused by other HPV types. During progression to cancer …

Cdc6p and the members of the minichromosome maintenance (MCM) family of proteins, which associate with the origin-recognition complex (ORC) at initiation of DNA replication, are downregulated and, indeed, absent in quiescent cells. Antibodies recognizing these proteins can therefore be used to detect proliferating cells specifically. In an exciting development, recent research has shown that these observations from basic research can be applied directly to cancer screening.

Carcinoma of the cervix is one of the most common malignancies. Papanicolaou (Pap) smear tests have reduced mortality by up to 70%. Nevertheless their interpretation is notoriously difficult with high false-negative rates and frequently fatal consequences. We have addressed this problem by using affinity-purified antibodies against human proteins that regulate DNA replication, namely Cdc6 and Mcm5. These antibodies were applied to sections and smears of normal and diseased uterine cervix by using immunoperoxidase or immunofluorescence to detect abnormal precursor malignant cells. Antibodies against Cdc6 and Mcm5 stain abnormal cells in cervical smears and sections with remarkably high specificity and sensitivity. Proliferation markers Ki-67 and proliferating cell nuclear antigen are much less effective. The majority of abnormal precursor malignant cells are stained in both low-grade and high-grade squamous intraepithelial lesions. Immunostaining of cervical smears can be combined with the conventional Pap stain so that all the morphological information from the conventional method is conserved. Thus antibodies against proteins that regulate DNA replication can reduce the high false-negative rate of the Pap smear test and may facilitate mass automated screening.