Tauno O. Ekfors

Acinar cell carcinoma of the pancreas

Pancreatic acinar cell carcinoma is a rare neoplasm (comprising about 1% of pancreatic tumours). We studied three cases (61‐year‐old female; 42‐year‐old male; 57‐year‐old male), whose survival after diagnosis ranged from 1 year 2 months to 6 years 8 months. There were widespread metastases in each case. The tumours had acinar, trabecular and solid growth patterns. By immunohistochemistry, pancreatic acinar cell markers including carboxyl ester lipase, pancreatic secretory trypsin inhibitor and pancreatic phospholipase A2 (group I PLA2) gave a strong positive reaction in all three cases. By electron microscopy, zymogen granules were seen in the cytoplasm of the tumour cells. Immunostaining for prostate‐specific antigen was positive in all three cases. Above‐normal concentrations of pancreatic PLA2 were measured in the serum of one patient and the values decreased during chemotherapy concomitantly with the reduction in the size of the tumour mass. In conclusion, immunohisto‐chemical demonstration of the secretory products of acinar cells including the new marker pancreatic PLA2 is useful in the differential diagnosis of pancreatic acinar cell carcinoma. Determination of the concentration of pancreatic group I PLA2 in serum may be helpful in the evaluation of therapy.

Loss of expression of the p16INK4/CDKN2 gene in cutaneous malignant melanoma correlates with tumor cell proliferation and invasive stage

The G1/S checkpoint of the cell cycle is regulated by p16, p53 and RB tumor suppressor genes. Loss of expression of the p16INK4 tumor suppressor protein, the product of the CDKN2 gene, has been associated with a wide variety of human malignancies. Mutations, loss of heterozygosity and deletions of the CDKN2 locus have been reported in sporadic and familial cutaneous malignant melanomas (CMM). To investigate the role of the alterations of p16 expression in melanoma, we evaluated by immunohistochemistry the p16 expression and cell proliferation in 79 primary CMM and 10 benign melanocytic nevi (BMN). Forty‐six melanomas (58%) and all BMN were found to be p16 positive; 33 melanomas (42%) were considered p16 negative. The extent of invasion according to Clark was significantly higher in p16‐negative tumors than in p16‐positive tumors. Cell proliferation as expressed by the proportion of positive cells in Ki‐67 immunostaining was found to be significantly higher in p16‐negative tumors than in p16‐positive tumors, although there was no significant difference in the mitotic index between p16‐positive and p16‐negative tumors. In p16‐positive tumors, the number of Ki‐67‐positive cells correlated with the mitotic index; in p16‐negative tumors, there was no correlation between these parameters. Our data suggest that loss of p16 expression is more common in advanced melanomas, and that G1/S checkpoint regulation is disrupted in p16‐negative melanomas. Our results show that loss of p16 expression is a common event in primary melanomas, which further substantiates the role of p16 as a major tumor suppressor. Int. J. Cancer 74:255‐259, 1997.

Distribution of a dipeptide naphthylamidase in rat tissues and its localisation by using diazo coupling and labeled antibody techniques

SummarySeveral rat tissues (liver, spleen, kidney, pancreas, skin, heart, lung and brain) were shown to contain a peptidase capable of liberating naphthylamine from glycyl-dl-proline naphthylamide (Gly-Pro-NA). A single DEAE-cellulose chromatography of autodigested homogenates of the above tissues produced a partial separation of the peptidase from the enzymes hydrolysing l-leucine β-naphthylamide. The Gly-Pro-NA hydrolysing enzyme was localised in tissue sections by using diazo coupling reaction and indirect immunologic techniques. Antibodies were prepared against the enzyme purified from rat liver and kidney in the rabbit. Rabbit γ-globulin was localized by using goat anti-rabbit γ-globulin labeled with fluorescein or with peroxidase.

Clear cell sarcoma of tendons and aponeuroses (malignant melanoma of soft parts) in the duodenum: the first visceral case.

An ulcerated tumour was removed by a Whipples operation from the descending part of the duodenum of a 38‐year‐old male. The tumour cells were mainly spindle‐shaped, arranged in nests and had very prominent nucleoli. A few cells contained melanin and melanosomes. Immunoreactivity for S‐100 protein and focally for HMB‐45 was observed. These features are diagnostic for clear cell sarcoma of tendons and aponeuroses. Because no other primary tumour could be found and the search for similar cases from the literature was unsuccessful, we believe that this tumour is the first reported clear cell sarcoma in a visceral location.

Decorin is produced by capillary endothelial cells in inflammation-associated angiogenesis.

Decorin is a small extracellular chondroitin/dermatan sulfate proteoglycan that has previously been shown to be involved in the angiogenesis-like behavior of endothelial cells (ECs) in vitro. There is also evidence that decorin plays a role in angiogenesis in vivo. In this study we sought to further explore the involvement of decorin in angiogenesis in vivo, especially in that associated with inflammation. We found by CD31 immunostaining of ECs that in giant cell arteritis there are capillary blood vessels not only in the adventitia as in uninvolved temporal artery wall, but also in the media and the external zone of the thickened intima. Localization of decorin by antiserum LF-30 in adjacent sections showed that in normal temporal artery wall decorin resides mainly in the media and the adventitia, whereas in inflamed temporal artery wall decorin is distributed throughout the vessel wall including the intima. Furthermore, the most intense reaction for decorin was evident in ECs of capillary neovessels within the media and the thickened intima of inflamed temporal artery wall. Decorin was also found in capillary ECs in certain pathological and physiological conditions in which the pivotal role of angiogenesis is more generally accepted. Pyogenic granulomas, granulation tissue of healing dermal wounds, and ovaries at different phases of follicle and corpus luteum formation all contained widely distributed CD31-positive capillaries. Decorin, on the other hand, was found in capillary ECs in pyogenic granulomas and granulation tissue, but not in those in the ovaries. The assessment of the degree of inflammation in the specimens with the presence of CD68-positive macrophages showed that the pyogenic granuloma, granulation tissue, and giant cell arteritis specimens were rich in macrophages around the decorin-positive capillaries. In contrast, the ovarian specimens were populated with fewer macrophages and even they were not located in close vicinity of capillaries negative for decorin. Our results confirm that decorin is involved in angiogenesis in vivo and, particularly, in conditions in which the inflammatory component is dominant.

Malignant rhabdoid tumor of the prostatic region

We describe a malignant rhabdoid tumour of the prostatic region in a 14-year old boy. The tumour showed positive immunoreactivity for epidermal prekeratin, monoclonal cytokeratin, epithelial membrane antigen, carcinoembryonic antigen and monoclonal vimentin but was negative for myoglobin, alfa-fetoprotein and lysozyme. Electron microscopy revealed pleomorphic cells with collections of paranuclear intermediate filaments, sheaves of tonofilaments and abundant microvilli in some tumour cells. Epithelial derivation was also suggested by occasional intracytoplasmic lumina and rare cell junctions.

THE USE OF IMMUNOHISTOCHEMISTRY TO IMPROVE SENSITIVITY AND SPECIFICITY IN THE DIAGNOSIS OF SYSTEMIC MYCOSES IN PATIENTS WITH HAEMATOLOGICAL MALIGNANCIES

The original histomorphological diagnoses in a series of 34 mycotic lesions from 23 patients with haematological malignancies were re‐evaluated by immunohistochemistry. A panel of antibodies was used to identify the agents of aspergillosis, candidosis, fusariosis, scedosporiosis (pseudallescheriosis), and zygomycosis. Apart from improving the diagnosis of aspergillosis, candidosis, and zygomycosis, the application of immunohistochemistry also disclosed three lesions of aspergillosis which had been overlooked during the original screening. It is concluded that the use of immunohistochemistry for the diagnosis of common opportunistic mycoses will not only increase diagnostic specificity, but will also reveal more tissue infections than the conventional histomorphological examination of traditionally stained sections.

Molecular profiling of human chondrosarcomas for matrix production and cancer markers

Chondrosarcoma is the second most common malignant bone tumor, characterized by production of abundant extracellular matrix resembling hyaline cartilage. To better understand the molecular pathogenesis of chondrosarcoma, we analyzed 12 chondrosarcomas for their production of connective tissue components and SOX9, a key regulator of normal chondrocyte differentiation. Furthermore, 10 chondrosarcoma samples were screened for additional changes in gene expression using cDNA array analysis. In Northern analysis, several tumors were found to express type II collagen mRNA at levels comparable to fetal cartilage used as a control. Interestingly, the highest levels of type II collagen mRNA were seen in 2 of the 3 grade 3 chondrosarcomas, which also exhibited the highest mRNA levels of SOX9 and “prechondrogenic” proα1(IIA) collagen. Expression of SOX9 in human chondrosarcomas is novel and suggests that chondrosarcomas originate from a multipotent stem cell committed to differentiation along the chondrogenic pathway. Results of the cDNA array analyses emphasize the heterogenous nature of chondrosarcoma as no single transcript was systematically up‐ or downregulated in all tumors analyzed. Among the interesting changes observed was upregulation of decorin mRNA in 7 of the 10 tumors analyzed. Further studies are needed to determine whether decorin plays a role in the pathogenesis of chondrosarcoma. The cDNA arrays also revealed discrepancies from Northern and RNase protection analyses in transcript levels of matrix components, emphasizing the need to validate cDNA array data with other techniques.

No improvement in the overall survival of 194 patients with chondrosarcoma in Finland in 1971–1990

We describe the clinicopathologic profile and survival of 306 patients with chondrosarcoma reported to the Finnish Cancer Registry in 1971–1990. 218 cases were available for reevaluation. Owing to their various clinicopathologic characteristics, we excluded the histologic variants of chondrosarcoma. Therefore, the final study population included 194 patients. The minimum follow-up was 9 years. The study population included 69 grade 1 tumors, 114 grade 2 tumors, and 11 grade 3 tumors. The commonest tumor sites were the chest, pelvis and femur. A local recurrence developed in 25% of the patients and metastatic lesions in 18%. The patients were treated in 31 hospitals (in 22 hospitals during the 1970s and in 26 in the 1980s), and the number of patients biopsied before the referral remained about the same from the 1970s (15%) to the 1980s (18%). The 5-and 10-year disease-specific survival rates were 70% and 57%, respectively. Multivariate analysis showed that the most important independent predictors of shortened survival were high histologic grade, age 50 years or older, and a diagnosis in the 1980s, as compared to the 1970s. Most findings accorded with reports from specialist treatment centers, but to our surprise, the survival rate declined among patients diagnosed in the 1980s versus the 1970s. The failure to improve patient survival is probably due to treatment of the patients in 31 hospitals rather than in a few centers dealing with treatment of cancer.

Immune responses and clinical outcome of massive human osteoarticular allografts

Cell mediated immune responses as measured by lymphocyte proliferation induced by the mitogens phytohemagglutinin and concanavalin A and antigen extracts of donor derived bone were studied within 2 years after wide resection of bone tumors in 18 patients receiving fresh frozen massive osteoarticular allografts. No uniform changes were seen in mitogen induced responses in 18 patients. However, five of nine patients tested with antigen extracts of donor derived bone showed elevated immune responses, one moderate and four weak. The incorporation of the allograft (evaluated by repeated radiographs; specific isotope techniques; clinical outcome assessed by the functional rating scores of Mankin-Waber and the Musculoskeletal Tumor Society; and histologic biopsy findings on new bone formation) did not differ in these patients from those in patients without any response to donor derived tissue. During a long term followup (mean, 11 years; range, 2–20 years), degenerative joint and sclerotic density bone changes developed after 2 to 4 years without correlation to immune responses. Histologic specimens showed no signs of immunologic reaction, and no clinical rejection episodes were recorded. A slightly variable immune response to allograft bone seems to occur, but its clinical significance for outcome of the grafts remains to be determined. The low immune responses might reflect a low antigen release rate through an indirect pathway or immunologic tolerance to antigens or proteins shed from massive allografts that are nonliving scaffold implants during the creeping substitution process, corresponding to the low immune response and the slow histologic repair.