Basal cell carcinoma and risk of subsequent malignancies: A cancer registry-based study in southwest England.

BACKGROUND: A possible link between basal cell carcinoma (BCC) and an increased subsequent risk of experiencing further noncutaneous malignancies has been suggested in previous cancer-registry and cohort studies. OBJECTIVE: The purpose of this study was to establish whether a possible link between BCC and subsequent malignancies could be confirmed in a new population in which environmental and genetic risk factors may vary from previously studied populations. METHODS: A cohort of 13,961 cancer registry-listed persons from the southwest of England, in whom BCC had been diagnosed during the period of 1981 to 1988, was examined for the relative risk of experiencing various further malignancies. RESULTS: An approximately 3-fold increase in the risk for malignant melanoma was demonstrated. No other cancers occurred in statistically significant excess. CONCLUSION: The previous reported associations of BCC onset with subsequent increased risk for various noncutaneous cancers are not supported by this study.

Head and neck cancer in the South West of England: influence of socio-economic status on incidence and second primary tumours.

This study examined possible links between the incidence of head and neck squamous cell carcinoma (HNSCC) and social deprivation. Data on all HNSCC registered between 1985 and 1991 in the South West of England were collected. Excluding tumours of the lip and skin there were 1570 cases, 72% in males. Of these, 1467 were identified as first primary tumours. Corrected chi-squared tests, accepting significance at the 5% level, were used to examine the association of socio-economic status (Carstairs index) with incidence at different sites. Overall, the incidence of HNSCC was higher in the socially deprived group. In males, the most deprived group had a significantly higher incidence of oral carcinoma than all other groups (P<0.05), whereas the incidence of laryngeal carcinoma showed a gradual rise with increasing deprivation. In females, where numbers were relatively low, the trend remained, but was less clear. In total, seventy-two (4.9%) cases went on to develop a second primary, of which 35% were in the lung and 13% in the bladder. Socio-economic status did not affect the development of a second primary tumour. The association of HNSCC with carcinoma of the bladder is a new finding.

An ecological study of cancer incidence and radon levels in South West England.

To investigate the relationship of domestic radon levels and cancer, the incidence of 14 major cancers in Devon and Cornwall were examined in relation to the local radon levels. Cancer registrations for 1989-1992 were provided by the South-Western Regional Cancer Registry. The average radon levels for postcode sectors were sorted into ten categories from low (< 40 Bq/m3) to extremely high (> or = 230 Bq/m3) and age-standardised incidence rates were calculated for each radon category. The incidence rates for lung cancer, where radon has been claimed to be a risk factor, were very similar across all domestic radon categories. Only non-melanoma skin cancers, showed a significant increase in incidence in the high-radon postcode sectors (> or = 100 Bq/m3) compared with the low-radon sectors (< 60 Bq/m3) and this effect was observed for both sexes. The remaining 12 cancer sites showed no significant trend in incidence rates with increasing radon concentration. There was no significant difference in corrected survival rates for any cancer site between the low- and high-radon areas. The possible contribution of confounding factors to the results of this study is discussed.

Uterine collagen during pregnancy in cattle.

Uteri were collected at the slaughter of non-pregnant dairy cattle and cattle at various stages of gestation. The weight of the whole uterus increased about 12-fold during the 9 month gestation period. The greatest increase was in the weight of the pregnant horn. The increase in weight of the uterine horns was accompanied by an increase in collagen content. The collagen concentration did not change. The collagen crosslink pyridinoline was identified in pregnant uterine tissues at a level of about 0.13 residues per mole of collagen; this level was the same at the beginning and end of pregnancy.

Improving the comparability of cancer registry treatment data and proposals for a new national minimum dataset.

BACKGROUND: There is no consistent or standardized practice for the collection of treatment data in UK cancer registries. This limits the usefulness and effectiveness of undertaking multiregional or national studies of treatment outcomes and survival. METHODS: A working group was established to examine the practices for recording the type and the amount of treatment data held in the cancer records at different registries. A common set of anonymized case notes for breast and colorectal cancer patients, drawn from each registry, was employed to eliminate any selection bias. Each registry coded these case notes according to their own criteria, and the comparability of such data between registries was determined from their returns. RESULTS: Of the 11 registries in England, seven participated in the full study, with a total of 84 records being submitted by five registries. A flow diagram was constructed to show how specific data items in the cancer record structure could be linked between registries. Errors or inconsistencies in recording treatment details were identified, and the constraints in data comparability were defined from the case note returns. CONCLUSION: Variations in coding practice between registries were such as to vitiate interregional or national comparisons of current data. The working group recommended an extended minimum dataset, which included a date for the start of each treatment modality, that most registries should be able to implement with some system changes.

Modelling post-mortem tenderisation-II: Enzyme changes during storage of electrically stimulated and non-stimulated beef.

Levels of calpains I and II, cathepsins B and L and ß-glucuronidase were determined in extracts of electrically stimulated and control beef M. Pectoralis profundus stored at temperatures between 0 and 30°C and varied to avoid muscle shortening. The level of lysosomal enzymes remained essentially unchanged throughout storage. The levels of calpain II were largely unaffected by the early treatments and decreased slightly throughout ageing. The level of calpain I, in both stimulated and control meats, was unaffected by temperature prior to the attainment of about pH 6·2 and thereafter the loss was accelerated at higher temperatures. In the extreme case studied, that of stimulated meat held at 15°C, 73% of the activity was lost in the first 24 h. After ageing, the level was about 11% of the initial when stored at 1°C and 25% when stored at 15°C. The exponential decay constants for the decrease in the levels of calpain I were 0·01 h(-1) at 1°C and 0·06 h(-1) at 15°C, and were the same as those for the previously determined rate of tenderisation. This suggested that the rate of proteolysis by calpain I was linked to the rate of tenderisation.

The effect of modification on the susceptibility of collagen to proteolysis: I. Chemical modification of amino acid side chains.

A series of chemically modified collagens were subjected to proteolysis by lysozomal cathepsins, pepsin and trypsin. Modifications of the collagens included acetylation, succinylation, methylation and borohydride reduction. Changes in the integrity of the materials were also monitored by differential scanning calorimetry (DSC). All modified collagens were implanted intramuscularly to assess their relative biodegradation rates in vivo. Methylation of the collagen showed extensive denaturation as confirmed by DSC, pepsin solublization to small fragments and by increased susceptibility to trypsin. However, methylation and succinylation made little difference to hydrolysis by cathepsins. Acetylation and borohydride reduction gave increased resistance to cathepsins as well as to pepsin, this latter also being found with the succinylated substrate. In-vivo implantation data showed both succinylation and methylation increased the rate of biodegradation but that the other modifications did not affect the rate of breakdown when compared with control unmodified collagen. The results of this study showed that chemical modification of collagen can alter in vivo degradation rates and could aid in designing collagen-based prostheses.

Uterine collagen during involution in cattle.

Post-partum involution of the bovine uterus was assessed by clinical examination and monitored biochemically by measuring the total urinary excretion of hydroxyproline and the collagen cross-link, pyridinoline. Uterine tissue contained 0.13 +/- 0.04 residues of pyridinoline per mole of collagen and negligible (less than 0.005 residues/mole) deoxypyridinoline. The pyridinoline/creatinine ratio was found to be a clearer and more reliable indicator of uterine resorption than the hydroxyproline/creatinine ratio. The amount of collagen cross-link excreted above baseline was equivalent to the amount of cross-link estimated to have been accumulated during pregnancy. Maximal excretion of pyridinoline occurred at day 6 and returned to baseline values in 2-3 weeks after parturition. An electron microscope study during the period of peak resorption revealed macrophage-like cells apparently engulfing or containing collagenous material, indicating phagocytic removal of the connective tissue.

The solubilization of myofibrillar proteins by calcium ions.

The effect of elevated levels (30 mm) of Ca(2+) and other divalent metals ions on rabbit psoas myofibrils was studied to determine whether these caused solubilization of structural proteins and if so whether the effect was due to salting-in or to proteolytic fragmentation resulting from activation of calpains. Incubation of myofibrils in 30 mm CaCl(2) at either pH 5·6 or 7·0 did not cause any apparent solubilization of the major Z-disc proteins, but there was an immediate ( < 1 min) solubilization of C-protein and troponin I together with small amounts of Mr 80 000 protein, troponin T and tropomyosin. Longer incubations with CaCl(2) extracted little additional C-protein but there was a steady increase with time in the solubilization of proteins with Mr values of 45 000 and 42 000, troponin T, tropomyosin and troponin I. Another high molecular weight protein of Mr 3-400 000 was extracted at pH 7·0 but not at pH 5·6. Similar results were obtained on incubation with 30 mm MgCl(2). In contrast to these findings, the same concentration of ZnCl(2) caused no detectable solubilization of myofibrillar proteins. The inclusion of proteinase inhibitors, E64, leupeptin, pepstatin or PMSF did not prevent the immediate solubilization of proteins. This showed that the solubilization of the proteins by Ca(2+) ions was due to salting-in rather than to proteolytic action by calpains.

Susceptibility of the cartilage collagens types II, IX and XI to degradation by the cysteine proteinases, cathepsins B and L.

We have investigated the susceptibility of both the helical and non-helical regions of isolated rat chondrosarcoma collagens, types II, IX and XI, to degradation by the cysteine proteinases, cathepsins B and L. Both enzymes degrade these collagens at temperatures from 20 to 37 degrees C and pH values from 3.5 to 7.0. Cleavage occurs only within the non-helical domains unless the helix is destabilized. Cathepsin L is more effective than cathepsin B on a molar basis and they appear to cleave at different sites. Since these cathepsins can degrade cartilage collagens at pH values near neutrality, they may contribute to the destruction of cartilage observed in arthritis.

Proteinase (Cathepsin B, D, L and Calpains) levels and conditioning rates in normal, electrically stimulated and high-ultimate-pH chicken muscle.

Control, electrically stimulated (ES) and glycogen-depleted (GD) chicken muscles were conditioned at 15°C with continuous mechanical testing for extensibility. The ES and GD muscles went into rigor 3·6 and 2·8 h earlier, respectively, than control muscle. At 24h post-rigor the extensibility of control muscle (11·2%) was markedly less than ES (19·2%) and GD (27·3%) muscles indicating that these latter two treatments should provide more tender meat. Measurement of sarcomere lengths showed no significant differences between control and GD muscle and thus, the greater extensibility in the high pH condition may be restricted to a wider separation of myofibriller fragments at the intermittent fracture zones when under load. Examination of muscle proteinase (cathepsins B, D and L, calpains I and II) and glycosidase (ß-d-glucuronidase, N-acetyl-ß-d-glucosaminidase) levels at 0 and 48h post-slaughter revealed changes in some key enzymes between the different treatments. Calpain I activity declined markedly during 48h storage of ES muscle (83%) compared to control (58%) and GD (63%) muscles. Cathepsin B and L activities did not decline during storage of ES muscle but there was a slight fall in control and GD muscles. Dosing of chicken shortly before slaughter with inhibitors of cysteine proteinases had a negligible effect on conditioning rate, apparently due to lack of inhibition of these proteinases during this short time period in the intact muscle.

Immunodetection of cathepsins B and L present in and secreted from human pre-malignant and malignant colorectal tumour cell lines.

Pre-malignant and malignant human colorectal tumour epithelial cell lines both secreted precursor forms of the 2 cysteine proteinases, cathepsins B and L. The amount of proteinases secreted by these cell lines varied according to the cell density. Comparison at similar cell densities showed that the pre-malignant, adenoma-derived cell line (PC/AA) secreted as much, or more, of both cathepsin B and L precursors as did the malignant, carcinoma-derived cell line (PC/JW/FI). However, mature forms of cathepsins B and L were detected in the culture media of only the carcinoma-derived cell line, thus indicating that the invasive potential of a tumour may be related to its ability to process extracellularly the secreted precursor enzyme to a mature and consequently active enzyme, rather than to the amount of proteinase synthesized and/or secreted. Similar results were obtained using 2 other epithelium-derived tumour cell lines, HT/29 (carcinoma) and SP/AN (adenoma). Immunolocation studies showed that cathepsin B was lysosomal while cathepsin L appeared to have a distribution more consistent with a plasma membrane association. Purified human cathepsins B and L (mature form) were capable of solubilizing an isolated basement membrane matrix (bovine anterior lens capsule) in vitro, thus indicating that the secreted mature enzymes and the membrane-associated cathepsin L could potentially degrade basal laminae or sub-endothelial basement membranes in vivo.

A comparison of four cathepsins (B, L, N and S) with collagenolytic activity from rabbit spleen.

We have separated four cathepsins (B, L, N and S) from rabbit spleen. They are all collagen-degrading cysteine proteinases, with Mr values of 25,250, 23,500, 34,000 and 30,000 for cathepsin B, L, N and S respectively. Cathepsins B, N and S have isoelectric points of 5.4, 6.2 and 6.8 respectively, whereas cathepsin L exhibited multiple charge forms in the range 5.0-5.7. A comparison of their specific activity against a variety of protein and synthetic substrates shows many differences. These differences can be visually illustrated through isoelectric focusing and detection of enzymic activity with protein and synthetic-substrate overlays. By using an enzyme-linked immunosorbent assay based on the binding to chicken cystatin and detection with polyclonal and monoclonal antibodies to native cathepsins B and L, no cross-reactivity of the four native enzymes was observed. Studies on the co-operative or synergistic effect in degrading collagen indicated that, of the different combinations tested, only the combination of cathepsin B and N exhibited enhanced collagenolysis.

Elevation of cathepsin L levels in the synovial lining of rabbits with antigen-induced arthritis.

The activity and distribution of the collagenolytic lysosomal enzyme, cathepsin L, has been assessed in the synovial lining of the rabbit during the initiation and development of chronic (antigen-induced) arthritis. Biochemical assay of homogenates of synovial lining revealed a marked increase in the activity of lysosomal enzymes, including cathepsin L, between 1 and 5 days following initiation of arthritis. Elevated levels of these enzymes were still present at 4 weeks duration of arthritis. Using a monospecific antibody to cathepsin L. enzyme was immunolocated only in synovial lining cells in normal joints. In arthritic joints the enzyme was found in synovial lining cells, synovial fibroblasts and in infiltrating macrophages. Measurement, by scanning and integrating microdensitometry, of the peroxidase-reaction product in synovial lining cells revealed an increased content of cathepsin L in these cells in the diseased tissues.

Microelectrode studies on the acid microenvironment beneath adherent macrophages and osteoclasts.

Osteoclasts and activated macrophages in culture were shown to generate an acidic microenvironment specifically in the attachment zone between the cell and the base of the culture dish. Measurements using pH microelectrodes revealed that osteoclasts, when firmly attached, could achieve a pH fall of about 1 unit min-1 to a limit value of pH 3.0 or less. Activated macrophages produced a slower fall of 0.5-2 pH units h-1 and a limit value of pH 3.6-3.7 was generally detected. The method of activation was relatively unimportant, but where macrophages formed clumps the pH effect was reinforced. Osteoclasts were also examined in situ in osteoporotic bone fragments in rabbit ear chambers, using a combination H+ and Ca2+ double-barrelled electrode. The pH readings reached a lower limit of 4.7 and the calcium concentration rose to a maximum of 40 mM in the erosion sites. In vivo such acid conditions would favor the direct extracellular action of secreted lysosomal proteinases in the degradation of collagen by both cell types.

Examination of cathepsins B, D, H and L activities in dry-cured hams.

Cathepsins B, D, H and L as well as the glycosidases ß-glucuronidase and N-acetyl-ß-glucosaminidase were assayed for activity in fresh pork muscles stored for up to 20 days at 4°C and in 3- and 8-month dry-cured hams. Cathepsin B, H and L activities fell by 40-79% after 20 days while cathepsin D activity remained unchanged. All the enzymes were still active after 8 months of dry curing; with the recoveries found to be in the range 14-73%. Contaminant microorganisms did not appear to contribute to the observed proteinase activities. Cathepsins B, H and L activities from the 8-month ham have been confirmed as cysteine proteinases by the use of specific inhibitors. It was further confirmed that the cathepsin B and L activities in fresh pork and dry-cured ham were similar by isoelectrofocusing. We suggest that the presence of the curing salts may be important in stabilising the muscle enzymes during the curing process.