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P B Silcocks

Publications and source records attributed to P B Silcocks.

8 recordsLinked to original sources
PubMed1992

Delay in fixation does not affect the immunoreactivity of proliferating cell nuclear antigen (PCNA).

The effect of delayed fixation on the immunoreactivity of proliferating cell nuclear antigen (PCNA) was investigated using eight breast carcinomas. Topologically shuffled samples of each tumour were immersed in fixative at times of 0.5, 1, 2, 4, 6, 18, and 24 h after surgical removal. In addition to a PCNA index (percentage of positive cells per 1200 tumour cells), a semi-quantitative PCNA grading system was used, based on estimates of more than or less than 50 per cent of positive tumour cells at each time interval. The PCNA index of six tumours increased by a mean of 10 per cent with a fixation delay of 24 h. The PCNA grade of all eight tumours showed no change with delayed fixation.

Antigens, Neoplasm↗
PubMed1992

Mutant p53 oncogene expression in keratoacanthoma and squamous cell carcinoma.

The tumour suppressor gene p53, located on the short arm of chromosome 17, encodes for a nuclear protein which regulates cell proliferation by inhibiting cells entering S-phase. p53 mutations are alleged to be the commonest genetic abnormality in human cancer. We studied mutant p53 oncoprotein expression, using PAb1801 monoclonal antibody immunohistochemistry, in 25 'ideal' keratoacanthomas and 26 well-, 19 moderately and 18 poorly differentiated squamous cell carcinomas of the skin. While there was a highly significant trend in the proportion of p53 oncoprotein-positive lesions from keratoacanthomas to poorly differentiated squamous cell carcinomas (chi 2 = 17.13, df = 1, exact P = 0.00003), p53 expression was inadequate for distinguishing keratoacanthoma from well-differentiated squamous cell carcinoma (chi 2 = 2.55, df = 1, exact P = 0.18; corresponding to a sensitivity of 0.84 and a specificity of only 0.36).

Carcinoma, Squamous Cell↗
PubMed1992

General practitioners, skin lesions and the new contract.

We reviewed all skin lesions received in our laboratory from general practitioners (GPs) during a three-month period before the introduction of the new contract for GPs and during the same period a year later. For comparison we also reviewed skin lesions received from the general and plastic surgeons. Particular attention was paid to the completeness of excision. There was a significant increase in the number of skin lesions removed in general practice after the introduction of the new contract. Both benign and malignant lesions were more likely to be incompletely excised by GPs compared with surgeons. The GPs first noted to carry out minor surgery after the new contract came into force were less likely to have completely excised lesions than their more experienced colleagues. We suggest the future monitoring of lesions removed in general practice, possibly by the formation of a joint audit group.

Biopsy↗
PubMed1991

A case-control study of dietary carotene in men with lung cancer and in men with other epithelial cancers.

Dietary carotene intake during the year before diagnosis was estimated for 96 men with lung cancer, 75 men with other epithelial cancers, and 97 hospital controls. Relative to those of men in the lowest third of carotene intake (less than 1,683 micrograms/day), the smoking-adjusted odds ratios for men in the middle (1,683-2,698 micrograms/day) and upper (greater than 2,698 micrograms/day) thirds of carotene intake were 0.67 and 0.45, respectively, for lung cancer (one-sided test for trend, p = 0.048) and 0.63 and 0.65, respectively, for other epithelial cancers (one-sided test for trend p = 0.074). The protective effect of estimated dietary carotene intake was considerably stronger than was the effect of total intake of carotene-rich vegetables and fruits (grams per day), providing some evidence that the protective factor is carotene itself rather than another component of vegetables and fruits.

Aged↗
PubMed1989

Making cancer statistics more informative: measures of the quality of recorded diagnosis in a population-based registry.

The quality of the recorded diagnosis is a major limit to the usefulness of Cancer Registry statistics that is easily overlooked by users of the data. With data from a large population-based cancer registry as an example, we demonstrate how Registry statistics could be improved by wider use of three simple indices, namely (1) the proportion histologically verified (adjusted for age), (2) the proportion of verified cases with an uninformative diagnosis, and (3) the proportion of cases that are staged. We believe that greater awareness of the deficiencies of Cancer Registry statistics will lead to a more critical interpretation of them, and help stimulate efforts to rectify matters.

Aged↗
PubMed1989

Can we achieve 100% ascertainment in cancer registration?

Completeness of ascertainment is a central issue for any disease register. We outline the process of cancer registration as carried out in a large population-based Registry and argue that none of the various methods proposed to estimate the completeness of ascertainment are satisfactory. We suggest an alternative way of looking at the issue and describe various constraints that hamper attempts to achieve complete registration.

Death Certificates↗
PubMed1986

Evaluation of PAS-diastase and carcinoembryonic antigen staining in the differential diagnosis of malignant mesothelioma and papillary serous carcinoma of the ovary.

A series of malignant mesotheliomas and papillary serous carcinomas of the ovary were stained using the periodic acid Schiff reaction with diastase digestion (PAS-D) and an immunoperoxidase technique for carcinoembryonic antigen (CEA). The methods were evaluated in terms of repeatability and validity. Staining reactions were classed as positive or negative by three 'blinded' observers. Within-observer repeatability was greater for PAS-D than for CEA but there was no statistically significant difference for between-observer repeatability. The validity of the methods clearly differed, however, since the sensitivity and specificity of CEA were consistently less than that of PAS-D. Our most consistent estimates of sensitivity and specificity were compared with those of other studies and the reasons for this difference were analysed. Positive PAS-D and CEA staining were uncorrelated but a combination of the two did not appear significantly superior to PAS-D alone. We believe that PAS-D remains the method of choice for differentiating peritoneal mesotheliomas and disseminated papillary serous carcinoma of the ovary in the absence of reliable evidence of an ovarian primary because the significance of CEA positivity in occasional mesothelial tumours remains to be determined.

Amylases↗