Altered expression of cell cycle regulatory proteins in benign and malignant bone and soft tissue neoplasms

BACKGROUND

The binding of cyclins to cyclin-dependent kinases regulates cell proliferation. Overexpression of cyclins is believed to deregulate the cell cycle in human tumors. Here the expression of G1 cyclins D1 and D3, and of Ki-67 in a variety of bone and soft tissue sarcomas was assessed as compared to adjacent normal tissue and to a subset of leiomyomas.

MATERIALS AND METHODS

Twenty-nine human bone and soft tissue sarcomas were evaluated. Tissue sections from each case were subjected to immunostaining for cyclin D1, cyclin D3 and Ki-67 using the avidin-biotin complex method.

RESULTS

Cyclin D1 nuclear positivity was detected in 28% of sarcomas and in none of the leiomyomas. Cyclin D3 nuclear positivity was present in 62% of sarcomas and in none of the leiomyomas. Ki-67 nuclear staining was positive in 86% of sarcomas but in only 16% of leiomyomas. In addition, upregulation of cyclin D1 was observed in leiomyosarcomas, pleomorphic sarcomas and gastrointestinal stromal tumors, but not in liposarcomas or osteosarcomas. Cyclin D3, however, was expressed in all of the sarcoma types including 2 out of 5 liposarcomas and 1 out of 4 osteosarcomas. The normal soft tissue adjacent to the tumors when present (10 cases) was negative for cyclin D1 and D3, and expressed Ki-67 in 5% of the cell nuclei. The expression of cyclin D3 was also noted in human sarcoma cell lines (SKLMS, MG63, SaOS-2 and HT1080) by Western blot.

CONCLUSION

The higher expression of cyclin D1 and D3 and of Ki-67 in bone and soft tissue sarcomas, as compared to leiomyomas and peritumoral normal soft tissue, suggests that high cyclin expression may contribute to deregulation of the cell cycle in bone and soft tissue tumors. These data suggest a role of cyclins in the process of human sarcomagenesis.

Cyclooxygenase-2 (COX-2) expression in human endometrial carcinoma and precursor lesions and its possible use in cancer chemoprevention and therapy

In recent years, the design of new antineoplastic agents that can halt the progression of human malignancies with minimal systemic damage has been at the forefront of cancer research, with cyclooxygenase-2 (COX-2) as a major target molecule. With an aim to demonstrate the expression and role of COX-2, the principal putative target of COX-2 inhibitor therapy, in endometrial adenocarcinoma (EACA) and precursor lesions, atypical complex hyperplasia (ACH) and endometrial hyperplasia (EH), an immunohistochemical (IHC) analysis of 22 primary human EACAs and 14 precursor lesions was carried out. Relevant clinicopathological data were tabulated from a random computer-generated sample of 22 primary EACA patients, treated by hysterectomy at our institution. Representative tumor sections including adjacent precursor lesions and normal endometrium (NE) were immunostained with human monoclonal anti-COX-2. Qualitative and semi-quantitative COX-2 IHC staining scores were determined based on the proportion of immunoreactive cells and the intensity of cytoplasmic COX-2 expression. Fisher's exact test and the Wilcoxon Rank Sum test were used for statistical analysis. Mean patient age was 68 years (range 51-93). All 22 EACAs were of endometrioid type, of which ten (45%) were grade I, eight (36%) grade II and four (18%) were grade III. Overall, four out of nine (44%) EHs, four out of five (80%) ACHs, and 18 out of 22 (88%) EACAs were COX-2 positive. The mean COX-2 IHC scores for EH and EACAs were 33 (SD 24.11) and 76 (SD 54.57), respectively (p = 0.022). Strong or moderate COX-2 expression was observed in 17 out of 22 (77%) adenocarcinomas as compared to two out of 14 (14%) of the precursor lesions (EH and ACH). The areas of adenomyosis were COX-2 positive, while myometrial smooth muscle and normal fallopian tube tissues stained negative for COX-2. The demonstration of frequent and strong expression of COX-2 in human EACAs supports a possible role for COX-2 inhibitors. Furthermore, an increasing expression of COX-2 from EH to invasive EACAs suggests potential usefulness of COX-2 inhibition to halt the progression of precursor lesions to invasive endometrial cancers.

Cyclooxygenase-2 (COX-2) overexpression in childhood brain tumors

The overexpression of COX enzymes has been demonstrated in human neoplasms at various sites, including the colon, gastrointestinal tract, lung, skin and recently in brain tumors. In this study, COX-2 receptor overexpression in primary childhood brain tumors was determined and the distribution pattern of COX-2 receptors was examined. A sensitive, 4-step, alkaline phosphatase conjugated antigen detection technique was used and a specific monoclonal antibody for medulloblastomas/ primitive neuroectodermal tumors (MEDs/PNETs), anaplastic, high-grade astrocytomas (ASTRs) and in glioblastoma multiformes (GMs) was employed. All of the 14 MEDs/PNETs observed demonstrated high levels of immunoreactivity (overexpression), with the highest immunostaining intensity (grades A and B). However, of the 14 subtypes of astrocytic tumors examined, the COX-2 receptor expression level did not even approach those of the MEDs/PNETs levels. However, significant differences were found when comparing low grade pilocytic ASTRs to high grade anaplastic ASTRs and glioblastomas. In two low grade pilocytic ASTRs, the expression level never exceeded 20%, while in high grade glial tumors (6 anaplastic ASTRs and 6 GMs) 30 to 50% of the tumor cells overexpressed COX-2 receptors, documenting an increase in COX-2 receptor overexpression with the increasing grade of the astrocytic tumor. In view of these findings, it would appear likely that COX-2 inhibitors may represent a chemo-preventive tool in treating childhood brain tumors, which are the leading cause of solid tumor cancer death in children under the age of 20.

Up-regulation of VEGF expression and related neo-angiogenesis in childhood high-grade gliomas: implications for anti-angiogenic anti-neoplastic therapy

Vascular endothelial growth factor (VEGF) is a homodimeric, disulfide-linked glycoprotein which exhibits endothelial cell-specific mitogenic properties. VEGF is also a potent inducer of vascular permeability. There is considerable experimental evidence that VEGF isoforms are strongly involved in provoking neoangiogenesis of neoplastic cells and, consequently, the growth and progression of primary neoplasms (i.e., astrocytic gliomas), including the formation of an invasive and metastatic immunophenotype (IP). During this immunohistochemical study, the presence and tissue localization of VEGF121 was observed in anaplastic, high-grade astrocytomas (AAs) and in glioblastoma multiforme (GBMs) employing the specific monoclonal antibody against it. A sensitive, four-step, alkaline phosphatase-conjugated antigen detection technique was used. The immunoreactivity demonstrated a cytoplasmic, cell surface and extracellular matrix localization pattern in more than 90% of the tumor cells, with high intensity immunoreactivity (++++, A,B) in every high-grade astrocytic glioma tissue. VEGF121 expression was identified mostly within the cytoplasm of tumor cells, suggesting an embryonic, undifferentiated and more malignant cellular IP of high-grade gliomas. Tumor-related neo-angiogenesis and endothelial cell proliferation were also present. The great majority of high-grade astrocytic gliomas are incurable with the three classic therapeutic modalities. In the future, the development of targeted anti-neoplastic treatment strategies, adapted to individual patients, will require molecular identification of the different classes of neoplasm (including subtypes of astrocytomas) according to their stages, biology, prognosis and therapeutic options.

Ascorbyl stearate inhibits cell proliferation and tumor growth in human ovarian carcinoma cells by targeting the PI3K/AKT pathway

Ascorbyl stearate is a lipophilic, vitamin C derivative with antitumorigenic properties. The molecular mechanism(s) underlying the anticarcinogenic effect of this compound have not been well documented. The effect of ascorbyl stearate was studied in a panel of human ovarian epithelial cancer cells. Treatment with ascorbyl stearate caused a dose-dependent inhibition of the cell proliferation. The antiproliferative effect was due to the arrest of cells in the S/G2-M-phase of the cell cycle. Treatment of OVCAR-3 cells with ascorbyl stearate also inhibited PI3K/AKT activity. The presence of a constitutively active AKT protected OVCAR-3 cells from the effects of ascorbyl stearate, suggesting that this nutraceutical targets the PI3K/AKT pathway. The administration of ascorbyl stearate by gavage induced involution of human ovarian carcinoma xenografts in nude mice. These studies indicate that the antiproliferative effect of ascorbyl stearate on ovarian epithelial cancer cells is associated with decreased PI3K/AKT activity, and point toward the PI3K/AKT signaling pathway as a target for this drug.

Differentiation-dependent expression and mitogenic action of interleukin-6 in human colon carcinoma cells: relevance for tumour progression

Interleukin (IL)-6 mRNA expression in general is low in normal, adenomatous and cancerous human colon mucosa, except in rather undifferentiated lesions, in which IL-6 is overexpressed. Cytokeratin (CK) 8-positive carcinoma cells were identified by double immunostaining as almost exclusive source of IL-6. Likewise, in five (sub)clones of primary culture COGA-1 and COGA-13 human colon carcinoma cells, and in three established cell lines (Caco-2/AQ, Caco-2/15 and HT-29), efficient translation of IL-6 mRNA into protein was observed only in the least differentiated COGA-13 cells. Notably, IL-1beta (5 ng/ml) enhanced IL-6 release in COGA-13 cultures by three orders of magnitude. Although all cell clones studied expressed the IL-6 receptor (IL-6R), rhIL-6 (1-100 ng/ml) had a significant effect on cellular proliferation only in highly differentiated Caco-2 cells. Our data imply that IL-6, when released from rather undifferentiated carcinoma cells, particularly in response to IL-1beta, can advance tumour progression through paracrine growth stimulation of normal or highly differentiated colon tumour cells with intact STAT-3-mediated IL-6 signalling.

Epidermal growth factor receptor (EGFR) expression in childhood brain tumors

Overactivation of epidermal growth factor receptor (EGFR) signaling has been recognized as an important step in the pathogenesis and progression of multiple forms of cancer of epithelial origin. Reports regarding EGFR family members in brain tumors are sparse and, thus, the significance of EGFR expression in childhood brain tumors is unclear. In this study, the expression of the EGFR family members was analyzed in 22 medulloblastomas. During the immunohistochemical study, a sensitive, four-step, alkaline phosphatase conjugated antigen detection technique was employed. The results demonstrated the presence of c-erbB-2 (HER-2) and c-erbB-4 (HER-4) in 10 to 50% of the neoplastic cells of high-grade glial tumors with high immunoreactivity, while c-erbB-3 (HER-3) was only detected in less than 10% of the neoplastically-transformed cells. In a follow-up, 70% of children, usually under 4 years of age, with c-erbB-2 (HER-2)-positive MEDs/PNETs, succumbed to the cancer. The Kaplan-Meier estimation revealed a significant correlation between c-erbB-2 expression and survival (p = 0.002), suggesting that c-erbB-2 (HER-2) is probably a prognostic marker for limited survival. Medulloblastoma is the most common malignant brain tumor that occurs during childhood. Multimodality treatment regimens have substantially improved survival in this disease; however, the tumor is incurable in about one-third of patients with medulloblastoma, and the current treatment has a detrimental effect on long-term survivors. As such, the results of this study further support the idea that targeting EGFR alone, or in combination with its downstream mediators, represents a promising new approach for the management of childhood brain tumors. Moreover, c-erbB-2 (HER-2) expression may also be of use in better classifying brain tumors.

Immunocytochemical detection of members of the caspase cascade of apoptosis in childhood medulloblastomas

During the process of programmed cell death (PCD), the cell disintegrates into small, membrane-bound apoptotic bodies. Caspase-3 is ubiquitously expressed in normal and neoplastically-transformed human cells and serves as an executioner in the apoptotic or PCD pathway. During our immunocytochemical study, a sensitive, four-step, alkaline phosphatase-conjugated antigen detection technique was employed. The results demonstrated the presence of apoptotic activity within the cellular microenvironment of childhood medulloblastoma/primitive neuroectodermal tumor. The observations identified the cytoplasmic presence of caspase-3 in more than 20% of neoplastic cells. The immunocytochemical expression pattern demonstrated a translocation tendency from the cytoplasm to the cell nuclei in the apoptotic cells in about 5% of the tumor cells. Caspase-3 presence was also detected in the tumor infiltrating lymphocytes (TILs), representing the host's immune, mostly CD8+, cytotoxic, tumor-associated antigen (TAA)-directed effector cells. This phenomenon may play an important role in these tumors' maintenance of immune privilege and evasion of immune attacks. We suggest that the grade and intensity of apoptosis may not only have diagnostic and prognostic significance, but could also play a leading role in the biological (fourth modality) antineoplastic treatment of these highly malignant, neuroectodermal brain tumors.

Survivin expression in childhood medulloblastomas: a possible diagnostic and prognostic marker

Survivin is a member of the inhibitor of apoptosis gene family that is expressed in embryonic tissues during human ontogenesis and most human malignancies, but it is not present in the majority of normal adult tissues. Survivin is also a chromosomal passenger protein required for physiological cell divison. Survivin blocks apoptosis, via its BIR domain, by either directly or indirectly blocking the function of the members of the caspase cascade. The expression of this apoptosis inhibitor protein in medulloblastomas (MEDs) was examined for the first time. During the immunohistochemical study, a sensitive, four-step, alkaline phosphatase conjugated antigen detection technique was employed. The results did, in fact, demonstrate the presence of survivin in 10 to 50 per cent of medulloblastoma (MED) cells with medium intensity immunoreactivity (++, B) in this neuroectodermal brain tumor. These results indicate that survivin is probably not only a diagnostic marker, but also an important prognostic marker for MEDs/PNETs and may be useful in the future grading of malignancy in MEDs, much as grading is done today for astrocytomas (ASTRs). Furthermore, the almost exclusive neoplastic expression of survivin will allow development of new antineoplastic, immunotherapeutic strategies.

Immunocytochemical detection of members of the caspase cascade of apoptosis in high-grade astrocytomas

During the physiological process of PCD, the cell initiates a sequence of events culminating in the disintegration of the cell into small, membrane-bound apoptotic bodies. The intrinsic part of the PCD program arises from the mitochondria when it releases cytochrome c from the mitochondrial intermembrane space into the cytosol, forming the caspase-activating complex or apoptosome. The family of caspases is involved in the execution of genetically controlled PCD. Caspase-3 is expressed in normal and neoplastically transformed human cells and, like other caspases, is synthesized as an inactive, 32kDa proenzyme. Caspase-6 cleaves nuclear mitotic apparatus protein (NuMA) and mediates the shrinkage and fragmentation of cell nuclei. Caspase-8 is an initiation caspase that activates the caspase cascade during apoptosis, while caspase-9 is the initiator caspase in the caspase cascade in apoptotic normal and neoplastically transformed cells. During our immunocytochemical study, a sensitive, four-step, alkaline phosphatase conjugated antigen detection technique was employed. The results did in fact demonstrate the presence of high apoptotic activity within the cellular microenvironment of high-grade astrocytomas and glioblastomas. The observations identified cytoplasmic expression of caspase-3 and caspase-6 in more than 50 per cent of tumor cells, caspase-8 and caspase-9 in more than 10 per cent of tumor cells in high-grade anaplastic ASTR and glioblastoma. The immunocytochemical expression pattern in about 10 per cent of the tumor cells for caspase-3 and caspase-6 and about 1 to 5 per cent of the tumor cells for caspase-8 and caspase-9 demonstrated a translocation tendency from the cytoplasm to the cell nuclei in the apoptotic cells. This phenomenon may play an important role in these tumors' maintenance of immune privilege and evasion of immune attacks. We suggest that caspase-3, -6, -8 and -9 immunocytochemistry could have prognostic and immunotherapeutic significance in the treatment of these highly malignant glial tumors.

Flat and polypoid adenocarcinomas of the colorectum: a comparative histomorphologic analysis of 47 cases

"Flat" colorectal adenomas and adenocarcinomas are well documented in the Japanese literature but only sporadically reported in the English literature. The present study involved systematic morphological analysis of a large series of colorectal carcinomas (CRCs) to determine the frequency of these "flat" CRCs (FCRCs) and analyze their pathological characteristics and associated patient survival. The study group comprised 47 patients (19 females and 28 males) with primary CRC who underwent colorectal resection at the H. Lee Moffitt Cancer Center between 1997 and 2002. These cases were selected based on the gross appearance of the tumors and after review of all of the hematoxylin and eosin-stained tumor sections in a series of 190 consecutive colorectal resections for CRCs. Application of strict morphological criteria classified 22 tumors as FCRCs. For comparison, 25 "polypoid" CRCs (PCRCs) were also identified. Cases of ulcerative fungating annular CRCs and CRCs with mixed gross appearance were excluded from this analysis. Clinicopathologic data, including patient survival, were compared for FCRCS and PCRCs. Statistical analyses were carried out using the chi(2) or Fisher's exact test and log-rank tests. Overall, 22 of 190 CRCs (11%) were found to meet the morphological criteria of FCRCs. Mean patient age was 70.6 years (range, 55 to 87) for FCRCs versus 68.5 years (range, 54 to 91) for PCRCs, and mean tumor size was 4.7 cm (range, 1.6 to 9) for FCRCs versus 4.4 cm (range, 0.5 to 10) for PCRCs. None of the 22 FCRCs and only 1 of 25 (4%) PCRCs were well differentiated; 17 of 22 (77%) FCRCs and 23 of 25 (92%) PCRCs were moderately differentiated; and 5 of 22 (22%) FCRCs and 1 of 25 (4%) PCRCs were poorly differentiated (P = 0.0087). FCRC cases were staged as 0 stage T1, 3 (14%) stage T2, and 19 (86%) stage T3; PCRC cases, as 4 (16%) stage T1, 14 (56%) stage T2, and 7 (28%) stage 3 (P = 0.000031). Similarly, angiolymphatic invasion was identified in 12 of 22 (54%) FCRCs versus 4 of 25 (16%) PCRCs (P = 0.0123). Although some differences between FCRCs and PCRCs were observed on resection in terms of nodal status (N), presence of metastases (M), and perineural invasion, these differences were not statistically significant. In comparison with PCRCs, FCRCs were associated with significantly shorter postresection patient survival at 1 to 5 years (P = 0.028). We have demonstrated in this report that a proportion of primary CRCs resected at our institution were indeed "flat." Furthermore, these FCRCs exhibited higher histological grades, higher T stage, more frequent angiolymphatic invasion, and shorter patient survival compared with PCRCs. Based on these data, FCRC appears to be a worse subtype of colon cancer than PCRC. Further appraisal of FCRCs and additional studies to further elucidate the molecular mechanisms underlying their morphogenesis are warranted.

Role of p53, CD44V6 and CD57 in differentiating between benign and malignant follicular neoplasms of the thyroid

The distinction between follicular adenoma (FAD) and follicular carcinoma (FCA) of the thyroid can be particularly challenging in routine practice of diagnostic surgical pathology. It often requires examination of several histologic sections in order to identify the presence of unequivocal capsular and/or vascular invasion. To investigate the role of immunohistochemical markers in the differential diagnosis of follicular lesions of the thyroid, we studied the pattern of expression of p53, Bcl-2 and of the adhesion molecules CD44V6 and CD57, in 20 FADs and 21 FCAs of the thyroid. Ninety percent of FCAs exhibited strong nuclear p53 expression. p53 stain was seen in only 15% of FADs (p<0.0001), and it was weak. Bcl-2 cytoplasmic immunoreactivity was observed in 57% of FCAs and 60% of FADs (p=1.00). Similarly, membranous CD44V6 staining was seen in 81% of FCAs, but in only 20% of FADs (p=0.0001). CD57 was present in the cytoplasm of 71% of FCAs and 15% of FADs (p=0.0004). None of the markers studied correlated with tumor size. The results of this study indicate that immunohistochemical detection of p53, CD44V6 and CD57 may have practical utility in the differential diagnosis of FCAs from FADs in routine surgical pathology.

Value of multilevel sectioning for improved detection of micrometastases in sentinel lymph nodes in invasive squamous cell carcinoma of the vulva

Clinical usefulness of sentinel lymph node (SLN) biopsy has been demonstrated in the management of early vulvar cancer. However, what constitutes a negative SLN has not been well defined. Furthermore, to what extent the SLNs should be sectioned for the greatest likelihood of detection of micrometastases and whether multilevel sectioning will further increase this detection rate in this setting have not been well studied. We analyzed 280 groin lymph nodes (SLNs=45, non-sentinel [NSLNs]=235) in 14 patients with invasive squamous cell carcinoma (ISCC) of the vulva treated with vulvectomy and inguinal SLN and NSLN dissection at the H. Lee Moffitt Cancer Center (HLMCC) between 1996 and 2001. Each SNL was evaluated for micrometastases by H&E and pancytokeratin AE1/3 (CKAE1/3) immunohistochemical staining. All negative SNLs (N=40) were sectioned times 3 (x3) at 50-micron intervals and independently reviewed by two pathologists in order to assess the utility of this inexpensive and logical approach to identifying additional micrometastases. Also, the Wilcoxon Rank Sum Test was used to determine if there was an association between tumor size, depth of invasion and SNL status. The patient age ranged from 35 to 81 years (mean 59 yrs); size of invasive tumor from 1.0 to 7.0 cm (mean 3.4 cm); depth of invasion from 3 to 25 mm (mean 10.8 mm). Of 45 SLNs examined from 14 patients, 11% (5/45) SNLs were positive for micrometastases on initial H&E and/or CKAE1/3 stains. Eighty-nine per cent (40/45) SNLs were negative in the remaining 9 patients. None of the latter 40 SNLs showed micrometastases on additional multilevel sectioning. Instead 3 of 135 NSLNs examined in these 9 patients revealed micrometastases on H&E (skip-micrometastases). Mean tumor size (cm) and depth of invasion (cm) were 4.06 (s.d. 1.89) and 1.20 (s.d. 0.35) for SLN (+) and 3.02 (s.d. 2.12) and 1.01 (s.d. 0.86) for SLN (-) tumor subsets (p values 0.385 and 0.348, respectively).

CONCLUSION

Following routine H&E and CK AE1/3 stains, multilevel sectioning does not appear to detect additional micrometastases in sentinel lymph nodes in squamous cell carcinoma of the vulva. Even though mean tumor size and depth of invasion were greater in SNL (+) as compared to SLN (-) tumor subsets in our series, this difference did not reach statistical significance.

Cyclooxygenase-2 Expression in Right- and Left-Sided Colon Cancer: A Rationale For Optimization of Cyclooxygenase-2 Inhibitor Therapy

Cyclooxygenase-2 (COX-2) has been identified as a potential target for prevention and therapy of human colorectal cancers (CRC) and other cancers. Because right-sided colon cancers (RSCCs) exhibit clinicopathologic and genetic differences from left-sided colorectal cancers (LSCRCs), determination of COX-2 status in these subsets of CRCs may be clinically relevant in designing COX-2 inhibitor trials for CRC and in subsequent assessment of objective therapeutic response to such therapy. Thirty-six primary CRC resection specimens (18 left, 18 right) from 36 patients were evaluated. Representative tumor sections were subjected to immunohistochemical analysis of COX-2. A semiquantitative system was used to score cytoplasmic COX-2 immunostaining. The tumors were considered COX-2 positive if more than 10% tumor cells showed COX-2 staining. Clinicopathologic and COX-2 data were compared for LSCRCs versus RSCCs. All 18 LSCRCs and 13 of 18 (72%) RSCCs were well to moderately differentiated. Overall rates of COX-2 positivity for the LSCRCs versus RSCCs were 67% (12 of 18) and 33% (6 of 18), respectively (P = 0.04). Furthermore, 11 of 12 (92%) COX-2 positive LSCRCs and 3 of 6 (50%) COX-2 positive RSCCs were stage II-IV at resection. All 12 COX-2 positive LSCRCs were associated with advanced primary tumor and 4 of 12 (33%) LCRCs had distant metastases. These associations could not be evaluated for the RSCCs because of the limited number of COX-2 positive cases. The more frequent expression of COX-2 in LSCRCs as compared with RSCCs supports the hypothesis that COX-2 expression may be related to genetic alterations specific to right- or left-sided CRCs. Further studies are needed to elucidate such relationships. Our data also suggest that stratification of patients with CRC into right- and left-sided subsets may be important in optimal patient selection for COX-2 inhibitor therapy and for subsequent assessment of objective therapeutic response.

Antigen presentation by dendritic cells and their significance in antineoplastic immunotherapy

Dendritic cells (DCs) are present in essentially every mammalian tissue, where they operate at the interface of innate and acquired immunity by recognizing pathogens and presenting pathogen-derived peptides to T lymphocytes. According to the research group of Shortman, experimental results suggest a "dual" DC differentiation model, demonstrating the existence of both myeloid-derived (with characteristic IF: CD11b+, CD11c+, CD8alpha- and DEC205+) and lymphoid-derived DCs (showing CD11b- CD11c-, CD8alpha+ and DEC205+ IF). DCs, including interdigitating cells (IDCs) and Langerhans cells (LCs), are characterized by dendritic morphology, high migratory mobility and are the most effective, "professional" cells for antigen presentation in primary immune responses. Most of the DCs express immunocytochemically detectable antigens like: S-100, CD1a, CD40 receptor, adhesion molecules (ICAM-1 or CD54, LFA-1 and LFA-3), integrins (CD11a, CD11c and CD18), CD45, CD54, co-stimulatory molecules (B7-1 or CD80, B7-2 or CD86), F418, MHC class I and II and DEC-205, multilectin receptor, immunostimulatory cytokine (IL-12) and, of course, Fc and complement receptors. Following recognition and uptake of antigens, mature dendritic cells (DCs) migrate to the T lymphocyte rich area of draining lymph nodes, display an array of antigen-derived peptides on the surface of major histocompatibility complex (MHC) molecules and acquire the cellular specialization to select and activate naive antigen-specific T lymphocytes. Immunotherapeutic ideas are based on the ability of the mammalian immune system to recognize neoplastically transformed cells. Immunotherapy of human neoplasms has always represented a very attractive fourth-modality therapeutic approach, especially in light of the many shortcomings of conventional surgical, radiation and chemotherapies in the management of neoplastically transformed cells. The cancer vaccine approach to therapy is based on the notion that the immune system could possibly mount a rejection strength response against the neoplastic cell conglomerate. The efficiency of DCs for T lymphocyte stimulation moved a number of research groups to develop DC- based immunotherapy approaches. The failure of cancer vaccines may be attributed to the relationship between host and neoplasm: through a natural selection process, the host facilitates the selective enrichment of clones with highly aggressive neoplastically transformed cells, being in various stages of differentiation and only during certain stages express neoplastic cell specific molecules.

Glutathione-S-transferase pi expression and activity is increased in colonic neoplasia

Glutathione-S-transferase (GST) isoenzymes are involved in the conjugation of glutathione to electrophilic carcinogens. Recent studies have shown increased levels and activities of GST in different tumors suggesting their role in carcinogen detoxification. This study compared GST activity levels and GST-pi protein expression in paired samples of colorectal cancer, adenoma and adjacent normal mucosa from a total of thirteen patients. GST was isolated from human colorectal specimens and assayed spectrophotometrically; Western immunoblot analysis was used to quantify GST-pi levels. GST activity was greater in both colorectal cancer and adenomas than in adjacent normal colonic tissue, although statistical significance was achieved only when comparing colorectal cancer to normal tissue. Based on these observations, we conclude that increased GST activity may be a useful marker of colonic neoplasia.

Insulin-like growth factor 1 receptor activates c-SRC and modifies transformation and motility of colon cancer in vitro

Colorectal carcinomas have been found to express increased levels of IGF1 and IGF1-R, as compared to normal or adenomatous colonic mucosa, and it has been postulated that a subset of colorectal cancers are under the autocrine regulation of the IGF1/IGF1-R system. In this study, we selected human colorectal carcinoma cell lines with high (SW620, HT29, L4A) and low (CaCo2, and HCT 116) expression of IGF1-R by flow cytometry. Compared to the IGF1-R(-) cells, the IGF1-R(+) cells revealed a more aggressive phenotype as demonstrated by a higher proliferation rate (approximately 2-fold increase) in response to IGF1, higher degree of transformation (approximately 5-to-15-fold increase in colony formation in soft agar), increased resistance to serum deprivation-induced apoptosis [1-7 apoptotic cells/5 microscopic fields, as compared to 37 to 101 apoptotic cells/5 microscopic fields of the IGF1-R(-) cells], and higher migratory capability measured by a wounding assay [IGF1-R(+) cells migrated a distance of up to 15 millimeters from the cut edge of the monolayer, while the IGF1-R(-) cells were able to migrate only 2-3 millimeters away from the same reference point]. While the cell lines overexpressing the IGF1-R had higher levels of Src activation, the use of a Src inhibitor reduced the IGF1-R protein expression, slowed down the proliferation of IGF1-R(+) cells, and reduced their colony formation in soft agar. Based on the above observations, we conclude that an overexpressed and activated IGF1-R may increase the degree of transformation and motility of colon cancer cells by activating c-Src.

Racial differences in childhood tumors

The purpose of this brief review is to inform the reader of the appearance of childhood neoplasms along racial and ethnic lines. The Lag time, general aspects and specific tumors, such as astrocytomas, medulloblastomas and those of the skin, including cases affecting the face and mouth, are discussed. Other tumors discussed are melanomas, those of the nasopharynx, liver, bone, Hodgkin's disease and especially leukemias as primary forms. Special emphasis was put on the racial and other variabilities producing various combinations and specific responses to treatment.

Vaccines for immunotherapy of breast cancer and prostate cancer: new developments and comparative aspects

This review summarizes the most recent findings and the newest approaches in the design of vaccines for breast cancer and prostate cancer. The antigens associated with breast cancer and prostate cancer and their use in vaccine development are discussed. We consider the comparative aspects in the new vaccines and focus on their clinical potential. The future directions in designing cancer vaccines are discussed.

Vascular stroma-derived endothelial colony forming progenitor cells adapt to tumour growth

Under appropriate nutrient agar culture conditions, primary or xenografted human and animal tumour biopsy-derived cell suspensions will form two types of colony. The first type, consisting of tight colonies of round cells which form tumours when introduced into nude mice, is of neoplastic origin. The second type of colony, the cells of which fail to form tumours on injection into nude mice, consists of loose colonies of larger, inter-connecting elongated bi- or tripolar cells and is thought to originate from vascular stroma-derived endothelial colony forming progenitor cells (V-ECPC). The likely importance of V-ECPC to tumour growth is emphasised by a positive correlation between the VECPC-derived endothelial cell colonies and both tumour vascularity and growth rate. A high cloning efficiency obtained from tumours of particularly intense vascular nature indicates that this cell is of importance in vascular adaptation and therefore tumour growth. In contrast, avascular, fibrotic tumour tissue yielded very low numbers of stromal vascular endothelial cell colonies. The results suggest that stromal vascular endothelial cell colonies do not arise from the mature fibroblastic elements of the tumour stroma, but rather from cells within actively growing regions. Tritiated thymidine uptake studies show that the vascular stroma-derived endothelial colony forming progenitor cells cell are cycling. Cell separation studies have characterized the as yet morphologically unidentified V-ECPC as having a sedimentation rate of 4.7 mm./hr and a mean density of 1.068 g/cm3 and hence a calculated volume of 450 microns 3.

Bacteria-related spontaneous and therapeutic remission of human malignancies

The development of specific immunotherapeutic approaches to cancer treatment is making progress. However, a crucial clinical break-through in cancer vaccination is still missing. Spontaneous clinical remissions of malignancies are a rare phenomenon. The mechanisms are not clear but there are remissions described in correlation with bacterial infections. The use of bacteria or bacterial components might be a promising path for non-specific immunotherapy of tumors and might be a helpful adjuvant for specific immunotherapy. Here, we briefly review spontaneous remissions of various malignancies in humans, the impact of bacterial infection on tumor regression and the utilization of bacterial components in clinical trials.

Preneoplastic lesions of the prostate-clinical, pathological and molecular biological aspects

Needle biopsy is the mainstay of definitive diagnosis of prostate cancer (PCA). While prostate-specific antigen (PSA) screening has facilitated early diagnosis of PCA, it has also resulted in an increase in the proportion of prostate biopsies showing various preneoplastic lesions (PNLs). At times such lesions are the sole finding in the limited amount of tissue available for assessment in an individual biopsy. Hence accurate identification of these lesions is important to avoid errors in the diagnosis of prostatic malignancy and in patient management. Furthermore, some interesting observations have been made regarding the molecular biological aspects of various PNLs during the last decade. In parallel with anatomic and physiological differences in various human races, racial differences have also been observed regarding the incidence of prostatic intra-epithelial neoplasia. This review focuses on prostatic intraepithelial neoplasia (PIN), atypical adenomatous hyperplasia (AAH) and atypical prostatic glands or atypical small acinar proliferation (ASAP) as putative preneoplastic lesions of the prostate. These lesions are reviewed with reference to their overall incidence, histopathological findings, histological differential diagnosis, clinical significance and molecular biological aspects.

MAGE-1, a cancer/testis-antigen, expression in childhood astrocytomas as an indicator of tumor progression

During the last decade, the aberrant expression of normal testicular proteins in neoplastically transformed cells became common knowledge. Cancer/testis-antigens (CTAs) represent a novel family of immunogenic proteins. The MAGE genes were initially analyzed from melanomas and turned out to have an almost exclusively neoplasm-specific expression pattern. This expression pattern might contribute to the genetic instability of neoplastically transformed cells. In normal adult tissues, most 23 human MAGE genes are expressed only in the testis, but only in the mitotic spermatogonia (germ cells) and in the primary spermatocytes. The immunocytochemistry was carried out on routine, formalin-fixed, paraffin-wax-embedded 3 to 4 mm thick astrocytoma (ASTR) tissue sections. A four step, indirect, biotin-streptavidin based method was employed with alkaline phosphatase enzyme conjugation. Immunocytochemical presence and cellular localization of the MAGE-1 CT-antigen, employing anti-MAGE-1 MoAB was observed only in anaplastic, high-grade ASTRs (100%), certainly including glioblastomas, in this study. The immunoreactivity was always heterogeneous, showing a cytoplasmic pattern and loosely grouped cells with similar staining characteristics being detected within the cellular and hormonal microenvironment of the ASTRs. We never identified MAGE-1, CT-antigen expression in the lowest grade, pilocytic ASTRs. The MAGE-1 CTA expression levels may also be used to evaluate the malignant and dedifferentiation tendencies of low-grade ASTRs and predict the likelihood of mutations of the genome and further dedifferentiation towards even more malignant anaplastic ASTR and glioblastoma multiforme IPs.

Expression of proline-directed protein kinase, (p34cdc2/p58cyclin A), a novel cell proliferation marker in childhood brain tumors

The presence of two proteins of the proline-directed protein kinase (PDPK), the catalytic subunit p34cdc2 and the regulatory subunit p58cyclin A was determined in seven primitive neuroectodermal tumors (PNETs), three choroid plexus neoplasms and eleven astroglial tumors. The highest expression was registered in the cellularly undifferentiated PNETs and glioblastoma multiforme from the astroglial malignant group. Rabbit immunoantiserum against the two subunits of PDPK, a cell proliferation marker, was employed to detect proliferation activity in childhood brain tumors. The PDPK activity was present from Gl- to M-phases in 21 childhood brain tumors with different central nervous system (CNS) localization and cellular atypia. Immunocytochemical analysis employed an indirect, alkaline phosphatase conjugated biotin-streptavidin antigen detection technique on frozen and routine, formalin-fixed and paraffin-wax-embedded tissue sections of brain tumors. We compared the proliferation activity in the cells of normal, morphologically changed and neoplastically transformed choroid plexus. The average proliferation activity was low in comparison with other tissues. The results in normal and neoplastically transformed choroid plexus were very similar. The lowest proliferation activity in the astroglial group belonged to pilocytic ASTRs. The use of cell differentiation as a prognostic factor in primary brain tumors has already been established and is strongly suggested by our research group. Further systematic neoplasm studies and regular employment of these two polyclonal antibodies for immunocytochemical screening experiments are necessary to determine their true diagnostic and prognostic significance.

COX-2, NSAIDs and human neoplasia. Part I: Colorectal neoplasms

Cyclooxygenase-2 (COX-2), the inducible cyclooxygenase isozyme involved in the conversion of arachidonic acid (AA) to biologically active prostanoids, has become the subject of intense interest during the last few years. The recent surge of interest stems from seminal studies that correlated elevated expression of COX-2 with tumor induction and progression, and epidemiological studies that correlated reduced risk of developing certain types of cancers with chronic use of non-steroidal anti-inflammatory agents (NSAIDs). Although these observations were first reported with colorectal cancer (CRC), similar findings have subsequently been made with other types of cancers. A wide spectrum of studies continue to be undertaken in both laboratory and clinical settings to elucidate the mechanisms underlying these anti-tumor effects of COX-2 for potential translation into cancer chemoprevention and therapy. The aim of this article is to present a review of COX genes, the prostaglandin-cyclooxygenase relationship, the role of COX-2 in carcinogenesis and the rationale for targeting COX-2 with NSAIDs for cancer chemoprevention. Special emphasis is given to the role of COX-2 expression in the genesis and progression of colorectal neoplasia, and its correlation with other pathological characteristics of CRC. Preliminary observations on COX-2 expression in inflammatory bowel disease (IBD)-related colorectal neoplasia are also presented.