Bell-shaped nuclei dividing by symmetrical and asymmetrical nuclear fission have qualities of stem cells in human colonic embryogenesis and carcinogenesis.

Large cell nuclei with at least eight distinct morphologies have been discovered throughout the fetal gut (5-7 weeks), colonic adenomas, and adenocarcinomas, five of which are not present in the normal adult colon. The most remarkable nuclear forms are hollow bells, approximately 10-15 microns in height and about 7-10 microns in bell mouth diameter. When encased in tubular syncytia, these bell-shaped structures divide symmetrically by an amitotic nuclear fission process resembling the separation of two paper cups. Seven other nuclear morphotypes emerge from the bell-shaped nuclei within the syncytia by asymmetrical amitotic nuclear fission. Cells containing these differentiated nuclear forms subsequently divide extra-syncytially by mitoses that form clonal populations of cells with identical nuclear morphotypes in embryos, adenomas, adenocarcinomas, and metastases. Cells with bell-shaped nuclei thus appear to be responsible for both net growth and differentiation in the embryonic gut, adenomas, and adenocarcinomas, and fulfill the requirements for post-embryonic stem cells in colon organogenesis and carcinogenesis.

Cables enhances cdk2 tyrosine 15 phosphorylation by Wee1, inhibits cell growth, and is lost in many human colon and squamous cancers.

Cyclin-dependent kinase 2 (cdk2) is a small serine/threonine kinase that regulates cell cycle progression. Cdk2 activity is tightly controlled by several mechanisms, including phosphorylation and dephosphorylation events. Cables is a recently described novel cdk-interacting protein. In proliferating cells, Cables was predominantly localized in the nucleus by cell fractionation and immunostaining. Expression of Cables in HeLa cells inhibited cell growth and colony formation. Cables enhanced cdk2 tyrosine 15 phosphorylation by the Wee1 protein kinase, an inhibitory phosphorylation, which led to decreased cdk2 kinase activity. The gene encoding Cables is located on human chromosome 18q11-12, a site that is frequently lost in squamous, colon, and pancreas cancers. We found that Cables was strongly expressed in normal human epithelial cells including squamous and glandular mucosa. Breast and pancreatic cancers show strong Cables expression; however, loss of Cables expression was found in approximately 50-60% of primary colon and head and neck cancer specimens. Lack of Cables expression was associated with loss of heterozygosity on chromosome 18q11. The data provide evidence for a Cables-mediated interplay between cdk2 and Wee1 that leads to inhibition of cell growth. Conversely, loss of Cables may cause uncontrolled cell growth and enhance tumor formation.

reply: Neurobiologyp25 protein in neurodegeneration.

Yoo and Lubec show that the amount of p25 is decreased in the brains they studied from patients with Alzheimer's disease or Down's syndrome. Their results persuaded us to conduct a more extensive survey of the p25/p35 ratio in AD brains (to be published elsewhere), as the number of samples was small in both of our studies (eight AD brains in our original study and six in theirs). After analysing a further 25 AD brains and those from 25 age-matched controls, we found that p25 levels are consistently higher in AD brains and that the difference is statistically significant (Student's t-test). This is in agreement with our original observations, as well as being consistent with earlier reports of increased Cdk5 kinase activity in AD brain and of increased amounts of p25 in an animal model of neurodegeneration.

Cables links Cdk5 and c-Abl and facilitates Cdk5 tyrosine phosphorylation, kinase upregulation, and neurite outgrowth.

Cyclin-dependent kinase 5 (Cdk5) is a small serine/threonine kinase that plays a pivotal role during development of the CNS. Cables, a novel protein, interacts with Cdk5 in brain lysates. Cables also binds to and is a substrate of the c-Abl tyrosine kinase. Active c-Abl kinase leads to Cdk5 tyrosine phosphorylation, and this phosphorylation is enhanced by Cables. Phosphorylation of Cdk5 by c-Abl occurs on tyrosine 15 (Y15), which is stimulatory for p35/Cdk5 kinase activity. Expression of antisense Cables in primary cortical neurons inhibited neurite outgrowth. Furthermore, expression of active Abl resulted in lengthening of neurites. The data provide evidence for a Cables-mediated interplay between the Cdk5 and c-Abl signaling pathways in the developing nervous system.

Pathologic features, proliferative activity, and cyclin D1 expression in Hurthle cell neoplasms of the thyroid.

Making a histologic distinction between Hurthle cell adenomas and carcinomas sometimes may be difficult. We analyzed a series of Hurthle cell lesions to determine whether specific histologic features and expression of Ki67 and cyclin D1 could be useful in distinguishing Hurthle cell adenomas from carcinomas. Formalin-fixed, paraffin-embedded tissues from 128 Hurthle cell neoplasms, including 59 adenomas; 55 carcinomas; and 14 tumors classified as neoplasms of uncertain malignant behavior (UMB), which had equivocal capsular invasion but no vascular invasion, were analyzed for expression of Ki67 and cyclin D1 by immunostaining. The distribution of immunoreactivity for Ki67 with antibody MIB-1 was analyzed by quantifying the percentage of positive nuclei that was expressed as the labeling index. None of the patients with adenomas or UMB tumors developed recurrent or metastatic disease after a mean follow-up of 7.8 and 7.9 years, respectively. Of the 55 patients with Hurthle cell carcinoma, 19 were associated with metastatic disease, 13 of whom died with disease. No patient with a Hurthle cell carcinoma without vascular invasion developed metastatic disease. The mean tumor size for Hurthle cell carcinomas (4.8 cm) was significantly larger than that of Hurthle cell adenomas (3.1 cm) or UMB tumors (3.7 cm). No patient with a Hurthle cell tumor smaller than 3.5 cm developed metastatic disease, even when vascular invasion was present. The Ki67 labeling index in Hurthle cell carcinomas (10.0 +/- 1.2) was 3-fold higher than in Hurthle cell adenomas (3.2 +/- 0.3). The Ki67 labeling index in the UMB group was 5.0 +/- 0.7. Cyclin D1 showed diffuse nuclear staining in 1 of the 59 (1.7%) Hurthle cell adenomas, in 10 of the 55 (18%) Hurthle cell carcinomas, and in none of the UMB tumors. In summary, analyses of the cell cycle proteins Ki67 and cyclin D1 in Hurthle cell thyroid neoplasms indicate that these markers may assist in distinguishing some Hurthle cell carcinomas from adenomas. Among the Hurthle cell carcinomas, large tumor size and vascular invasion are associated with clinically aggressive tumors. Our study also suggests that Hurthle cell neoplasms with only equivocal capsular invasion and no vascular invasion should behave in a benign manner.

Conversion of p35 to p25 deregulates Cdk5 activity and promotes neurodegeneration.

Cyclin-dependent kinase 5 (Cdk5) is required for proper development of the mammalian central nervous system. To be activated, Cdk5 has to associate with its regulatory subunit, p35. We have found that p25, a truncated form of p35, accumulates in neurons in the brains of patients with Alzheimer's disease. This accumulation correlates with an increase in Cdk5 kinase activity. Unlike p35, p25 is not readily degraded, and binding of p25 to Cdk5 constitutively activates Cdk5, changes its cellular location and alters its substrate specificity. In vivo the p25/Cdk5 complex hyperphosphorylates tau, which reduces tau's ability to associate with microtubules. Moreover, expression of the p25/Cdk5 complex in cultured primary neurons induces cytoskeletal disruption, morphological degeneration and apoptosis. These findings indicate that cleavage of p35, followed by accumulation of p25, may be involved in the pathogenesis of cytoskeletal abnormalities and neuronal death in neurodegenerative diseases.

Cyclin D1 overexpression combined with N-nitrosomethylbenzylamine increases dysplasia and cellular proliferation in murine esophageal squamous epithelium.

We previously described the oral-esophageal tissue-specific expression of cyclin D1 with the Epstein-Barr virus ED-L2 promoter in transgenic mice, and resulting dysplasia. Given the evidence for an interplay between environmental and genetic factors in esophageal squamous carcinogenesis, the aim of this study was to determine the potential cooperation of the nitrosamine compound N-nitrosomethylbenzylamine (NMBA), an esophageal specific carcinogen, in the cyclin D1 transgenic mice. NMBA was first demonstrated to induce dysplasia in two strains of inbred mice, C57BL/6 and FVB/N. Subcutaneous NMBA was then administrated to wild type and transgenic mice beginning at 4 weeks of age. Mice were monitored for the duration of the study for general appearance, activity and weight, and were euthanized at 12 and 15 months. Histopathologic analysis revealed increased severity of dysplasia in cyclin D1 mice treated with NMBA compared with treated age-matched wild-type mice and untreated mice. There was also increased proliferating cell nuclear antigen (PCNA) expression in the esophagi of NMBA treated cyclin D1 mice. Taken together, these findings suggest that a genetic alteration, specifically cyclin D1 overexpression and a chemical carinogen, NMBA, may cooperate to increase the severity of esophageal squamous dysplasia, a prominent precursor to carcinoma.

Absence of cyclin D1 protein expression in splenic marginal zone lymphoma.

Splenic marginal zone lymphoma (SMZL) is a recently recognized primary splenic lymphoma. SMZL can be associated with peripheral lymphocytosis, in which some cells have a villous morphology (splenic lymphoma with villous lymphocytes [SLVL]). Several recent studies suggested involvement of the bcl-1 locus and/or the cyclin D1 gene, located on chromosome 11q, in SMZL/SLVL. Translocation t (11;14) is associated with rearrangement of the bcl-1 locus and overexpression of the cyclin D1 gene. Both the translocation and cyclin D1 protein expression are characteristic of mantle cell lymphoma (MCL) and are rare in other lymphoid neoplasms; thus, their detection is useful in the diagnosis of MCL. Because the differential diagnosis of low-grade lymphoma in the spleen can be difficult, it is important to assess the frequency of cyclin D1 expression in SMZL to determine its usefulness in differential diagnosis from MCL. We analyzed the expression of cyclin D1 nuclear protein in paraffin sections using an immunoperoxidase technique in 17 cases diagnosed as SMZL. In eight cases, the presence of cyclin D1 mRNA was also assessed by Northern blot analysis. None of the 17 cases of typical SMZL showed expression of cyclin D1 mRNA or protein. In contrast, four cases used as controls showed either expression of cyclin D1 protein or mRNA or both. We conclude that assessment of cyclin D1 protein expression can be useful in distinguishing SMZL from MCL involving the spleen.

BCL-1 (PRAD-1/cyclin D-1) overexpression distinguishes the blastoid variant of mantle cell lymphoma from B-lineage lymphoblastic lymphoma.

The blastoid variant of mantle cell lymphoma (MCL-BV) can occur de novo or can represent a morphologic transformation of MCL associated with aggressive clinical disease. Its cytologic appearance is very similar to that of lymphoblastic lymphoma (LBL) because of its characteristic nuclear features and high proliferative rate. To assess the usefulness of antibodies to cyclin D-1 (BCL-1/ PRAD-1), CD99 (12E7), CD34, and TdT in distinguishing between MCL-BV and LBL in formalin-fixed, paraffin-embedded tissue, we studied from the Stanford data base 10 cases originally diagnosed as B-lineage LBL, 5 MCL-BVs, 2 cases thought likely to represent MCL-BV, and 2 blastic lymphomas whose morphology and immunophenotype were indeterminate. Six (60%) of 10 LBLs stained with CD99, as opposed to none of 7 MCL-BVs. Four (40%) of 10 LBLs reacted with CD34, as compared with none of 7 MCL-BVs. Eight (89%) of nine LBLs were positive for TdT, but all of the four MCL-BVs tested were negative. In contrast, the anti-cyclin D-1 antibody stained the nuclei of all of the MCL-BVs and none of the LBLs tested. On the basis of our evaluation, the probable MCL-BV cases were considered to be definite MCL-BV. Of the indeterminate cases, one was considered to be LBL, whereas we felt that the other represented MCL-BV. We conclude that staining formalin-fixed, paraffin-embedded, high-grade lymphomas with anti-cyclin D-1 antibody is useful in confirming the diagnosis of MCL-BV, whereas positive reactions with CD99, CD34, and particularly TdT are more characteristic of LBL.

The targeting of the cyclin D1 oncogene by an Epstein-Barr virus promoter in transgenic mice causes dysplasia in the tongue, esophagus and forestomach.

Cyclin D1 in cooperation with its major catalytic partners, cyclin-dependent kinases cdk4 and cdk6, facilitates progression through the G1 phase of the eukaryotic cell cycle, in part through phosphorylation of the retinoblastoma protein. Cyclin D1's oncogenic properties have been suggested by its cooperation with ras or adenovirus E1a to transform cultured cells, as well its overexpression in transgenic mice that leads to breast cancer. Activated by a number of different mechanisms in human cancers, the cyclin D1 gene is frequently amplified in squamous epithelial cancers derived from the head/neck and esophageal regions. In order to study the functional consequences of cyclin D1 overexpression in these squamous epithelial specific sites, we have linked the Epstein-Barr virus ED-L2 promoter to the human cyclin D1 cDNA and utilized this transgene to generate founder lines. This transgene is transcribed specifically in the tongue, esophagus and forestomach, all sharing a stratified squamous epithelium. The transgene protein product localizes to the basal and suprabasal compartments of these squamous epithelial tissues, and mice from different lines develop dysplasia, a prominent precursor to carcinoma, by 16 months of age in contrast to age-matched wild-type mice. This transgenic model is useful in demonstrating cyclin D1 may be a tumor initiating event in aero-upper digestive squamous epithelial tissues.

Immunohistochemical detection and gene amplification of cyclin D1 in mammary infiltrating ductal carcinoma.

The deregulation of cyclin D1 (BCL-1, PRAD1, CCND1) protein, normally synthesized in the G1 phase of the cell cycle, has been implicated in the pathogenesis of some malignant neoplasms, including invasive mammary carcinomas. We used rabbit polyclonal antibody 19 to detect cyclin D1 in 55 infiltrating ductal carcinomas and compared the findings to six important clinicopathologic parameters and cyclin D1 gene amplification. Nuclear immunoreactivity of variable intensity for cyclin D1 was present in 35% of the neoplasms, whereas immunoreactivity of normal mammary epithelial nuclei was absent. No significant correlations were observed between immunoreactivity and patient age, axillary lymph node status, estrogen receptors, progesterone receptors, histologic grade, or any of its three components. There was a correlation between cyclin D1 immunostaining and tumor size (P = 0.013). Fourteen of 15 tumors 2 cm or less were negative, whereas 7 of 12 neoplasms larger than 4 cm were immunopositive. Fifteen percent of the invasive carcinomas had cyclin D1 gene amplification. Of these eight tumors, six showed cyclin D1 immunoreactivity (P = 0.017). In this study, cyclin D1 was detected immunohistochemically in approximately one-third of infiltrating ductal carcinomas; approximately one-third of these had detectable cyclin D1 gene amplification. These results further implicate cyclin D1 in breast tumorigenesis and are additional evidence for the role of cell cycle regulatory proteins in invasive mammary carcinoma.

Expression of the retinoblastoma protein in low-grade B-cell lymphoma: relationship to cyclin D1.

The product of the retinoblastoma tumor-suppressor gene (pRB), a nuclear phosphoprotein that regulates transcription factors such as E2F, is involved in cell cycle control and differentiation. Its activity is regulated by phosphorylation; the underphosphorylated form inhibits transcription whereas the highly phosphorylated form is inactive. Cyclin D1 and its associated kinase (CDK 4/6) phosphorylate pRB in vitro, and therefore are thought to contribute to the regulation of pRB function. To examine the effect of cyclin D1 overexpression on pRB in primary tumor tissue, we studied pRB expression in low-grade B-cell neoplasms, with particular regard to mantle cell lymphoma, which is characterized by cyclin D1 (bcl-1) overexpression. pRB expression was studied by immunostaining with a well-characterized anti-pRB antibody; the phosphorylation status of pRB was examined by immunoblots; and the functional binding capacity of pRB was examined by in vitro binding to adenovirus E1A protein. We studied 3 reactive lymph nodes, 28 low grade B-cell lymphomas, 4 cases of hairy cell leukemia (HCL) and 3 plasmacytomas. Reactive lymph nodes showed intense pRB staining of germinal centers, with strongest (2+) staining in the large cells (centroblasts) of the proliferating (dark) zone and weak or no staining of small lymphocytes, including those of the mantle zone. In B-chronic lymphocytic leukemia (B-CLL) (4 cases), follicular lymphoma (3 cases) and mucosa-associated (MALT) lymphoma (3 cases) strong (2+) pRB staining was limited to centroblasts in reactive and neoplastic follicles and occasional proliferation centers, with only faint staining of small lymphoid cells. In contrast, 15 of 16 cases of mantle cell lymphoma showed strong (1-2+) staining of most cells; one blastoid mantle cell lymphoma showed only faint pRB staining. All cases of (HCL) and plasmacytoma showed strong pRB staining. Although most lymphomas with strong pRB expression were cyclin D1(+), three cyclin D1(+) cases showed only weak pRB expression (1 B-CLL, 1 blastoid mantle cell, 1 unclassifiable low grade B-cell lymphoma). Conversely, of the 4 pRB(+) HCLs and 3 pRB(+) plasmacytomas, only 1 of each was cyclin D1(+). pRB appeared to exist primarily in the underphosphorylated (fastest migrating) form on Western blot, despite the fact that cyclin D1 was complexed to CDK4, a form in which it normally phosphorylates pRB. In addition, pRB appeared to be unmutated, because it bound normally to the adenovirus E1A protein and showed nuclear localization by immunostaining. We conclude that most cases of mantle cell lymphoma, HCL, and plasmacytoma show high levels of pRB in contrast to follicle center lymphoma and small lymphocytic lymphoma; however, pRB expression does not appear to be consistently related to cyclin D1 overexpression. The pRB appears to be unmutated and underphosphorylated, and therefore should be in its active form. Our data from primary lymphoma tissue suggests that overexpression of cyclin D1, whereas tumorigenic, does not lead to pRB loss or hyperphosporylation. Thus, the mechanism by which cyclin D1 contributes to tumorigenesis and the significance of the restricted expression of pRB in low-grade lymphoid neoplasms remain to be determined.

Immunohistochemical detection of p53, bcl-2, and retinoblastoma proteins in follicular lymphoma.

Mutations of p53 have been suggested to be involved in the histologic transformation of follicular lymphoma, but the role of the retinoblastoma (RB) gene, another tumor suppressor gene, in lymphomagenesis has not been established. To determine the roles of these tumor suppressor genes and their relationship with the anti-apoptotic bcl-2 gene in follicle center lymphoma, the immunohistochemical expression of p53, bcl-2, and RB proteins was correlated with cytologic grade in 50 cases of follicular lymphoma, and the results were compared to 23 cases of diffuse large B-cell lymphoma. The results showed that only 2 of 25 grade 1 follicular lymphoma were p53-positive compared to 16 of 25 grade 3 cases (P <.0001). A significantly lower number (13 of 25) of grade 3 follicular lymphomas expressed bcl-2 compared to grade 1 cases (23 of 25) (P <.004). Eight of 14 bcl-2-negative follicular lymphomas expressed p53, compared with 10 of 36 bcl-2-positive cases (P = .1). Twenty-four of 25 grade 3 follicular lymphomas showed 2+ to 3+ staining for RB protein compared to 9 of 21 grade 1 cases (P <.0002). Expression of p53 protein correlates significantly with higher cytologic grade in follicular lymphoma. Similar to earlier studies of breast cancer and lymphoma, there appears to be an inverse relationship between p53 and bcl-2 expression in follicular lymphoma. Inactivation of the retinoblastoma gene does not seem to be involved in the histogenesis of follicle center lymphoma or diffuse large B-cell lymphoma.

The morphologic spectrum of non-Hodgkin's lymphomas with BCL1/cyclin D1 gene rearrangements.

BCL1/PRAD1 gene rearrangements involving the cyclin D1 gene are a feature of about 70% of centrocytic/mantle-cell lymphomas (CC/MCL) but are identified in only a small proportion of other B-cell non-Hodgkin's lymphomas. Of 37 lymphomas found to have BCL1/cyclin D1 (PRAD1, CCND1) gene rearrangements, 30 fit the morphologic and immunophenotypic criteria for typical CC/MCL. Seven cases with morphologic features atypical for CC/MCL were identified. CD5+ monoclonal B cells were documented in all these cases. Six cases were subsequently stained for cyclin D1 protein, and all showed nuclear positivity. Five cases had variably sized foci of cells with moderately abundant pale cytoplasm resembling parafollicular/monocytoid B cells, marginal zone cells, hairy cells, or even proliferation centers. Transformed-appearing cells were also present in some lymphomas. In one case, striking follicular colonization created a markedly nodular growth pattern mimicking a follicular lymphoma. A sixth case had a marked predominance of small, round lymphocytes at some sites, mimicking a small lymphocytic lymphoma. Five of these six cases also had areas more typical of CC/MCL. The seventh case was a CD5-positive splenic marginal zone-like lymphoma (SMZL) with plasmacytic differentiation and circulating villous lymphocytes consistent with a splenic lymphoma with villous lymphocytes (SLVL). These cases illustrate the morphologic spectrum of small B-cell lymphoid neoplasms that have BCL1/cyclin D1 gene rearrangements and overexpression of cyclin D1. Despite the BCL1 translocation and cyclin D1 overexpression, the splenic lymphoma with plasmacytic differentiation was definitely not a CC/MCL and fit the clinicopathologic entity of SMZL/SLVL. The other six cases are best considered CC/MCL variants based on a combined morphologic, immunophenotypic, and genotypic evaluation. Genotypic or immunophenotypic studies to identify cyclin D1 rearrangements and overexpression, although not pathognomonic, are useful in recognizing these variant CC/MCL cases, which can mimic almost any of the other well-described but more indolent low-grade B-cell lymphomas and leukemias. Some of the variant CC/MCL cases had features in common with the CD5+ cyclin D1+ SMZL/SLVL, suggesting a possible relationship between these two otherwise distinct entities.

Cyclin D1/PRAD1 expression in parathyroid adenomas: an immunohistochemical study.

The cyclin D1 (PRAD1) oncogene is rearranged with the PTH gene and is transcriptionally activated in a subset of parathyroid adenomas. Because of heterogeneity in rearrangement breakpoints, the true percentage of adenomas with cyclin D1 deregulation is unknown. Overexpression of the cyclin D1 protein in parathyroid adenomas appears to be a unifying consequence of all cyclin D1 gene rearrangements and can, therefore, be examined to more comprehensively identify adenomas in which cyclin D1 is pathogenetically important. We studied cyclin D1 expression in 65 parathyroid adenomas (from 64 patients), 51 normal parathyroid glands (from the same patients), and 4 parathyroid carcinoma specimens (from 3 patients) using a microwave-enhanced immunohistochemical method and affinity-purified cyclin D1 polyclonal antiserum. When available, data on adenoma mass, intact PTH level, and concurrent serum calcium level were also collected. Twelve of the 65 adenomas (18%) showed diffuse nuclear staining of approximately 30-70% of the tumor cells. All 51 normal glands were negative, except 1 gland that showed scattered cells ( < 10%) with positive nuclear staining. In addition, scattered positive cells were seen in the compressed rim of histologically normal parathyroid tissue surrounding 2 adenomas that were cyclin D1 negative. No significant differences in adenoma mass, intact PTH levels, or concurrent calcium levels were found between positive and negative tumors. Two of 4 parathyroid carcinoma specimens from 2 of 3 patients showed strong nuclear staining for cyclin D1. Overexpression of the cyclin D1 oncogene in 18% of our cases, due to the cyclin D1/PTH translocation and/or other mechanisms, suggests that overexpressed cyclin D1 plays a role in the pathogenesis of a much larger proportion of parathyroid adenomas than previously appreciated. Cyclin D1 overexpression is a feature of typical parathyroid adenomas and is not confined to unusually large, symptom-causing adenomas as had been suggested by early DNA studies. Although only three patients with parathyroid carcinoma were studied, two of the patients' tumors stained for cyclin D1, raising the possibility that the frequency of cyclin D1 overexpression may be even greater in carcinomas. Cyclin D1 overexpression appears to highlight a central pathway in parathyroid neoplasia.

Oncogenic collaboration of the cyclin D1 (PRAD1, bcl-1) gene with a mutated p53 and an activated ras oncogene in neoplastic transformation.

Cyclin D1 is one of the key regulators in G1 progression in the cell cycle and is also a candidate oncogene (termed PRAD1 or bcl-1) in several types of human tumors. We report a collaboration of the cyclin D1 gene with ras and a mutated form of p53 (p53-mt) in neoplastic transformation. Transfection of cyclin D1 alone or in combination with ras or with p53-mt was not sufficient for focus formation of rat embryonic fibroblasts. However, focus formation induced by co-transfection of ras and p53-mt was enhanced in the presence of the cyclin D1-expression plasmid. Co-transfection of ras- and p53-mt-transformants with the cyclin D1-expression plasmid resulted in reduced serum dependency in vitro. Furthermore, the transformants expressing exogenous cyclin D1 grew faster than those without the cyclin D1 plasmid when injected into nude mice. These observations strengthen the significance of cyclin D1 overexpression through gene rearrangement or gene amplification observed in human tumors as a step in multistep oncogenesis; deregulated expression of cyclin D1 may reduce the requirement for growth factors and may stimulate in vivo growth.

Squamous cell carcinoma of the endometrium: a report of eight cases and a review of the literature.

BACKGROUND: Endometrial squamous cell carcinoma is extremely rare, with only 56 cases reported in the literature. METHODS: Six cases of endometrial squamous cell carcinoma were found in a review of 1182 cases of uterine corpus cancer treated at the Massachusetts General Hospital from 1975 to 1993. Two additional cases were seen in pathological consultation. The clinicopathological features of these 8 cases and the 56 reported cases were analyzed. RESULTS: The average age of the patients was 67 years; almost all of them were postmenopausal. The most frequent presenting symptom was vaginal bleeding. Chronic pyometra and nulliparity were predisposing factors. The average duration of symptoms before diagnosis was 11.5 months. Total abdominal hysterectomy with bilateral salpingo-oophorectomy was the primary treatment in 58 patients. Eighty percent of the patients with Stage I tumors survived; the median follow-up time was 32 months. The survival rate for patients with Stage III tumors was only 20%, and all 6 patients with Stage IV disease died. CONCLUSIONS: The preoperative diagnosis of endometrial squamous cell carcinoma may be difficult, since curettage specimens may show only highly differentiated squamous epithelium. The strong relationship between tumor stage and survival suggests that early diagnosis and treatment are imperative.

A pancreatic endocrine tumor arising within a serous cystadenoma of the pancreas.

We report a pancreatic endocrine tumor arising within an otherwise benign pancreatic serous cystadenoma in a 47-year-old woman with a history of lupus treated by steroids. She presented 10 years before resection with epigastric pain and intermittent jaundice. Histologic and immunohistochemical studies showed that the solid endocrine component was composed of small, uniform cells with stippled nuclei, which were chromogranin A positive. The surrounding cystic component was lined by periodic acid Schiff's-positive, diastase-digestible cells containing glycogen. To the best of our knowledge, this is the first case of a serous cystadenoma of the pancreas that contains a well defined pancreatic endocrine tumor reported in the English literature.

CD5+ extranodal marginal zone B-cell (MALT) lymphoma. A low grade neoplasm with a propensity for bone marrow involvement and relapse.

Three cases of extranodal marginal zone B-cell lymphoma (low grade B-cell lymphoma of mucosa-associated lymphoid tissue [MALT] type) in which the neoplastic B cells expressed the CD5 antigen are reported. The patients included 2 men and 1 woman, aged 44, 62, and 77 years. In all three cases, the histologic features were typical of marginal zone/MALT lymphoma, with reactive follicles, marginal zone (centrocyte-like) cells, and plasma cells. Pseudofollicles, prolymphocytes, and paraimmunoblasts were absent. In all cases, lymphoma from one or more sites expressed monotypic immunoglobulin (2 IgM kappa, 1 IgM lambda), pan B cell antigens and CD5. Two of 3 cases expressed CD43; one case expressed CD23. No case showed overexpression of the bcl-1 protein, cyclin D1. Interphase cytogenetic analysis revealed trisomy 3 in one of two cases examined. The two male patients presented with lymphoma in the ocular adnexa. One of them had marrow involvement, cervical lymphadenopathy and peripheral blood involvement at presentation; 24 months later, he developed a relapse in subcutaneous tissue. The second patient had marrow involvement 3 years later, at the time of recurrence of his orbital disease. The third patient presented with lymphoma at the base of the tongue. She subsequently developed lymphoma involving the left upper eyelid and right lacrimal sac and duct, the marrow, and the nasopharynx between 63 and 95 months after initial presentation. All of these patients presented with disease involving sites in the head and neck and all had multiple relapses or recurrences with bone marrow involvement at the time of presentation (1 case) or at relapse (2 cases). The presence of CD5 may be a marker for cases of MALT lymphoma with a tendency for persistent or recurrent disease, for dissemination to the marrow and other extranodal sites, and for leukemic involvement of the peripheral blood.