Fatal gastrointestinal bleeding due to IgA vasculitis complicated with tuberculous lymphadenitis: A case report and literature review.

We report a case of IgA vasculitis that developed during the treatment of tuberculosis. Patients with tuberculosis who are on antituberculosis treatment can be administered steroids for severe disease or complications.

Early Tumor Shrinkage as a Predictive Factor for Outcomes in Hepatocellular Carcinoma Patients Treated with Lenvatinib: A Multicenter Analysis.

We investigated the association between early tumor shrinkage (ETS) and treatment outcome in patients with hepatocellular carcinoma treated with lenvatinib (LEN). A retrospective analysis was performed in 104 patients. ETS was defined as tumor shrinkage at the first evaluation in the sum of target lesions' longest diameters from baseline according to the Response Evaluation Criteria in Solid Tumors (RECIST). The median overall survival (OS) was not reached, whereas the median progression-free survival (PFS) was 5.0 months. The receiver operating characteristic curve analysis in differentiating long-term responders (PFS ≥ 5.0 months) from short-term responders (PFS < 5.0 months) revealed an ETS cut-off value of 10%. ETS ≥ 10% was significantly correlated with better PFS and OS compared with ETS < 10%. Additionally, ETS ≥ 10% showed a better discrimination ability on prognosis compared with modified RECIST-based objective response at the first evaluation. Multivariate analysis confirmed ETS ≥ 10% as an independent predictor of better OS, as well as a Child-Pugh score of 5 and macrovascular invasion. In conclusion, ETS ≥ 10% was strongly associated with outcome in patients treated with LEN. This biomarker could allow earlier assessment of the treatment response and guide treatment decision-making for HCC.

Impact of Relative Dose Intensity of Early-phase Lenvatinib Treatment on Therapeutic Response in Hepatocellular Carcinoma.

BACKGROUND: Factors associated with response to lenvatinib have not been clarified in patients with hepatocellular carcinoma (HCC). PATIENTS AND METHODS: This study retrospectively analyzed 50 patients treated with lenvatinib as first-line therapy between March 2018 and March 2019. Patients were divided into two groups by the Modified Response Evaluation Criteria in Solid Tumours (mRECIST) (responders and non-responders, whose best overall responses were complete (CR)/partial response (PR) and stable (SD)/progressive disease (PD), respectively). Factors associated with response were assessed, including the relative dose intensity 8 weeks after lenvatinib induction (8W-RDI). RESULTS: The best overall responses were 0/22/14/14 of CR/PR/SD/PD. Multivariate analysis revealed that only 8W-RDI was significantly associated with response. The receiver operating characteristic curve for 8W-RDI in differentiating responders from non-responders revealed a cut-off value of 75%. Patients with 8W-RDI ≥75% experienced a higher response rate and longer progression-free survival than patients with 8W-RDI <75%. CONCLUSION: Our results suggest that maintaining an RDI ≥75% during the initial 8 weeks of lenvatinib treatment has a favorable impact on response.

Specific Conformational Change in Giant DNA Caused by Anticancer Tetrazolato-Bridged Dinuclear Platinum(II) Complexes: Middle-Length Alkyl Substituents Exhibit Minimum Effect.

Derivatives of the highly antitumor-active compound [{cis-Pt(NH3)2}2(µ-OH)(µ-tetrazolato-N2,N3)]2+ (5-H-Y), which is a tetrazolato-bridged dinuclear platinum(II) complex, were prepared by substituting a linear alkyl chain moiety at C5 of the tetrazolate ring. The general formula for the derivatives is [{cis-Pt(NH3)2}2(µ-OH)(µ-5-R-tetrazolato-N2,N3)]2+, where R is (CH2)nCH3 and n = 0 to 8 (complexes 1-9). The cytotoxicity of complexes 1-4 in NCI-H460 human non-small-cell lung cancer cells decreased with increasing alkyl chain length, and those of complexes 5-9 increased with increasing alkyl chain length. That is, the in vitro cytotoxicity of complexes 1-9 was found to have a U-shaped association with alkyl chain length. This U-shaped association is attributable to the degree of intracellular accumulation. Although circular dichroism spectroscopic measurement indicated that complexes 1-9 induced comparable conformational changes in the secondary structure of DNA, the tetrazolato-bridged complexes induced different degrees of DNA compaction as revealed by a single DNA measurement with fluorescence microsopy, which also had a U-shaped association with alkyl chain length that matched the association observed for cytotoxicity. Complexes 7-9, which had alkyl chains long enough to confer surfactant-like properties to the complex, induced DNA compaction 20 or 1000 times more efficiently than 5-H-Y or spermidine. A single DNA measurement with transmission electron microscopy revealed that complex 8 formed large spherical self-assembled structures that induced DNA compaction with extremely high efficiency. This result suggests that these structures may play a role in the DNA compaction that was induced by the complexes with the longer alkyl chains. The derivatization with a linear alkyl chain produced a series of complexes with unique cellular accumulation and DNA conformational change profiles and a potentially useful means of developing next-generation platinum-based anticancer drugs. In addition, the markedly high ability of these complexes to induce DNA compaction and their high intracellular accumulation emphasized the difference in mechanism of action from platinum-based anticancer drugs.

Naturally occurring branched-chain polyamines induce a crosslinked meshwork structure in a giant DNA.

We studied the effect of branched-chain polyamines on the folding transition of genome-sized DNA molecules in aqueous solution by the use of single-molecule observation with fluorescence microcopy. Detailed morphological features of polyamine/DNA complexes were characterized by atomic force microscopy (AFM). The AFM observations indicated that branched-chain polyamines tend to induce a characteristic change in the higher-order structure of DNA by forming bridges or crosslinks between the segments of a DNA molecule. In contrast, natural linear-chain polyamines cause a parallel alignment between DNA segments. Circular dichroism measurements revealed that branched-chain polyamines induce the A-form in the secondary structure of DNA, while linear-chain polyamines have only a minimum effect. This large difference in the effects of branched- and linear-chain polyamines is discussed in relation to the difference in the manner of binding of these polyamines to negatively charged double-stranded DNA.

Structurally Diverse Polyamines: Solid-Phase Synthesis and Interaction with DNA.

A versatile solid-phase approach based on peptide chemistry was used to construct four classes of structurally diverse polyamines with modified backbones: linear, partially constrained, branched, and cyclic. Their effects on DNA duplex stability and structure were examined. The polyamines showed distinct activities, thus highlighting the importance of polyamine backbone structure. Interestingly, the rank order of polyamine ability for DNA compaction was different to that for their effects on circular dichroism and melting temperature, thus indicating that these polyamines have distinct effects on secondary and higher-order structures of DNA.

Hepatitis C virus relapse was suppressed by long-term self-injection of low-dose interferon in patients with chronic hepatitis C after pegylated interferon plus ribavirin treatment.

AIM: The recommended treatment for chronic hepatitis C is a combination of pegylated interferon (PEG IFN) plus ribavirin (RBV). However, the sustained virological response (SVR) rate of PEG IFN-RBV therapy was approximately 50% in patients with genotype 1b and a high viral load. Thus, we compared the efficiencies and side-effects of PEG IFN-RBV and self-injected low-dose natural (n) IFN-α in patients with hepatitis C virus (HCV). METHODS: A prospective, multicenter, open-label study was conducted in 12 Japanese institutions. A total of 129 patients with chronic hepatitis C and no detectable HCV after 24-72 weeks of PEG IFN-RBV treatment were assigned to the control (n = 82) or treated (n = 47) group. Treated patients received 3 million units of nIFN-α 2-3 times/week over 96 weeks. The groups were compared regarding treatment efficiency and side-effects. RESULTS: Significant treatment success regarding virus negativation rates was found, with 89% and 73% for the treated and control groups, respectively (P = 0.039). In contrast, there was no difference in relapse rate between the groups 24 weeks after the 96-week nIFN-α treatment (P = 0.349). However, when early viral responders and late viral responders (LVR) were separated, LVR patients responded significantly to the treatment with 90% sustained virological response, compared to 53% for the control group (P = 0.044). The side-effects of nIFN-α were less than that of PEG IFN-RBV treatment. CONCLUSION: Self-injected nIFN-α has larger benefits than prolonged PEG IFN-RBV for chronic hepatitis C patients with high viral loads of genotype 1b who fail to achieve early viral response during initial combination treatment.

Double-Filtration Plasmapheresis plus Interferon-ß for HCV-1b Patients with Non-Sustained Virological Response to Previous Combination Therapy.

BACKGROUND AND AIMS: Double-filtration plasmapheresis (DFPP) together with interferon (IFN) administration produces a substantial reduction in the viral load during the early stages of treatment. METHODS: Based on their responses to previous pegylated IFN and ribavirin (PEG-IFN/RBV) therapy, 20 patients were divided into null virological response (NVR; n = 12) and relapse (n = 8) groups. DFPP was used in combination with IFN-ß/RBV with subsequent administration of PEG-IFN-α2a/RBV therapy (DFPP + IFN-ß/RBV then PEG-IFN/RBV). Early viral dynamics was assessed, focusing especially on complete early virological response (cEVR) associated with sustained virological response. Additionally, the interleukin 28B gene, the IFN/RBV resistance-determining region, the IFN sensitivity-determining region and the core regions were analyzed. RESULTS: Rapid virological response was achieved in 0% (0/12) of NVR and in 75% (6/8) of relapse patients, with a significant difference between the two groups (p = 0.001). Similarly, cEVR was achieved in 8% (1/12) of NVR and in 88% (7/8) of relapse patients, with a significant difference between the two groups (p = 0.037). By multivariate logistic regression analysis, interleukin-28B major was a significant determiner of cEVR (odds ratio = 24.19, p = 0.037). CONCLUSION: DFPP + IFN-ß/RBV then PEG-IFN/RBV therapy is indicated more for relapse than for NVR patients.

Pegylated interferon plus ribavirin combination therapy for chronic hepatitis C with high viral load of serum hepatitis C virus RNA, genotype 1b, discontinued on attaining sustained virological response at week 16 after onset of acute pancreatitis.

Recent clinical trials have shown that pegylated interferon-alpha (PEG-IFN-alpha) in combination with ribavirin (RBV) improves the rate of sustained virological response (SVR), with over 50% of patients demonstrating a positive response to treatment. However, no SVR has been reported when PEG-IFN/RBV combination therapy is discontinued by week 16, especially in cases of chronic hepatitis with a high viral load of serum hepatitis C virus (HCV) RNA, genotype 1b. Here, we describe SVR in a 67-year-old woman whose PEG-IFN/RBV combination therapy for chronic hepatitis C with a high viral load of serum HCV RNA, genotype 1b, was discontinued after 16 weeks because of the onset of PEG-IFN plus RBV-induced acute pancreatitis. Among viral factors, substitution of amino acid 70 (Arg) and 91 (Leu) in the core region and HCV RNA negativity were observed after 8 weeks. Host factors including low body weight, no alcohol consumption, no coinfection with hepatitis B virus, slight fibrosis, and viral factors including early viral clearance, double wild type in the core region, may have contributed to the SVR irrespective of the discontinuation of the combination therapy at week 16. Moreover, PEG-IFN plus RBV-induced acute pancreatitis might have been related to the SVR.

Acute Pancreatitis Associated with Pegylated Interferon and Ribavirin Treatment of Chronic Hepatitis C, Genotype 1b with High Viral Load.

Acute pancreatitis, an uncommon side effect of pegylated interferon α (PEG-IFN α) and ribavirin (RBV) combination therapy, has rarely been reported in the English language literature. Here, acute pancreatitis associated with PEG-IFN plus RBV treatment is described in three patients with chronic hepatitis C, genotype 1b with high serum hepatitis C virus RNA levels. The patients had been started on weekly subcutaneous injections of PEG-IFN α (60, 80, and 90 µg) plus a daily oral dose of RBV (600 mg). The therapy was discontinued, however, because of the onset of acute pancreatitis (after 15 weeks, 48 weeks, and 3 weeks respectively). The drug-induced pancreatitis was diagnosed on the basis of elevated levels of amylase and lipase and the absence of other identifiable causes. High tumor necrosis factor-α was found in one patient and high interleukin-6 in the other two. The immune system stimulated by PEG-IFN and RBV combination therapy might have caused the acute pancreatitis. Further study is needed to clarify the mechanism of the onset of drug-induced pancreatitis by PEG-IFN and RBV combination therapy.

Early reduction of infected hepatocytes by activated immunity at the time of interferon withdrawal hepatitis followed by lamivudine administration resulted in higher seroconversion in hepatitis Be antigen-positive patients with chronic hepatitis B.

BACKGROUND: It has been found that the efficacy of lamivudine (LAM) therapy can be improved by preceding administration with a short course of corticosteroid that induces a flare of the disease upon its withdrawal. Because of the side effects of corticosteroid, we tested the effect of a short course of interferon (IFN) as the primer instead of prednisolone, which was followed by LAM when the hepatitis flare occurred. The incidence of LAM resistance mutations and the effect of core promoter and precore mutations on the durability of the responses were also studied. METHODS: Patients treated with interferon (IFN)-LAM therapy (n=73) were compared to those treated with IFN alone (n=117). The IFN-LAM group received IFN-alpha MU/day, t.i.w. for a 3-month period. LAM (10mg/day during 1 year) was started when IFN withdrawal hepatitis occurred during 2-10 months after stopping IFN. The LAM-resistant, core promoter, and precore mutations were examined by sequencing. RESULTS: (1) The IFN-LAM group developed exacerbated hepatitis following IFN withdrawal in 63 patients before starting LAM therapy. The seroconversion (SC) rate was significantly higher in the IFN-LAM group than in the IFN-alone group (61% vs 26%, P=0.0001). (2) The LAM resistance mutation rate was 31% at 1 year after initiating LAM therapy. (3) In a stepwise discriminant-function analysis, decreased level of HBeAg determined at 4 weeks after LAM administration and increased level of HBeAb before the start of LAM administration contributed significantly on seroconversion to anti-HBe (P = 0.0073 and 0.004, respectively). (4) The reappearance rate of HBeAg within 6 months after the therapy (relapse) was 33% in the IFN-LAM group and 10% in the IFN-alone group. The prevalence of core promoter and precore mutations did not change before and after the therapy, nor did these mutations correlate with the relapse after stopping IFN-LAM therapy. CONCLUSIONS: (1) Our findings suggest that early reduction of infected hepatocytes expressed by HBeAg by LAM may contribute to a high SC rate of IFN-LAM therapy. (2) The emergence of LAM-resistant mutations was similar to the previously reported rate, and neither core promoter nor precore mutations correlated with relapse of seroconverters after IFN-LAM withdrawal.

RET gene rearrangements (RET/PTC1 and RET/PTC3) in papillary thyroid carcinomas from an iodine-rich country (Japan).

BACKGROUND: The frequency of RET rearrangements (RET/PTC) in papillary thyroid carcinomas varies significantly according to geographic area, with the greatest incidence reported in the Belarus region, which is iodine-deficient and was contaminated severely after the Chernobyl reactor accident, and with the lowest incidence in iodine-rich, nonirradiated Japan. The authors investigated the prevalence of RET/PTC in a large number of thyroid tumors from Japanese patients. METHODS: Fresh and paraffin embedded tumor tissues from 215 Japanese patients were examined for RET rearrangements (RET/PTC1 and RET/PTC3) by means of reverse transcriptase-polymerase chain reaction analysis, with primers flanking the chimeric region, followed by direct-sequence analysis. RESULTS: RET/PTC was found only in papillary carcinomas and was not observed in other histologic types of thyroid tumors. The overall frequency of RET/PTC in papillary carcinomas was 28.4%, with a greater frequency in younger patients, including 41.9% of younger patients age < 20 years, 27.6% of patients age 20-40 years, and 24.8% of patients age > 40 years. Among the patients in these 3 age groups, the prevalence rate of RET/PTC1 was similar, but RET/PTC3 was observed most frequently among patients age < 20 years. When the tumors were grouped further according to histologic subtypes, the prevalence of RET/PTC3 was greater in solid/solid-follicular papillary carcinomas than in classic papillary carcinomas. CONCLUSIONS: The results indicated that RET/PTC may be useful as a specific molecular marker for papillary thyroid carcinomas. Furthermore, its incidence in such tumors was not low in Japanese patients, and it seemed to be associated with patient age. Therefore, the current results raise questions regarding the belief that the frequency of RET/PTC differs geographically and is especially low in Japan.

The predictive value of liver fibrosis in determining the effectiveness of interferon and lamivudine therapies for chronic hepatitis B.

BACKGROUND: To determine the best indicator of the effective use of interferon and lamivudine for the treatment of hepatitis B e antigen-positive chronic hepatitis, we retrospectively analyzed histologic and virologic status in 200 patients who were treated with interferon and 45 patients who were treated with lamivudine. METHODS: Histological grading and staging scores were determined by international criteria and the METAVIR scoring system. The YMDD motif associated with lamivudine resistance was analyzed by the sequencing of hepatitis B virus (HBV) DNA. RESULTS: Of 200 interferon-treated patients, 62 (31%) seroconverted to anti-hepatitis B e (anti-HBe). Multivariate analysis showed that the significantly important predictors of response were a higher grading score (P = 0.0056) and lower staging score (P = 0.0010). Twenty (44%) of the 45 lamivudine-treated patients seroconverted to anti-HBe, and multivariate analysis showed that the significantly important predictors of response were a higher alanine aminotransferase (ALT) level (P = 0.0034) and lower hepatitis B e antigen levels ( P = 0.0128). YMDD mutations occurred during therapy in 12 patients (27%). The significantly important predictor of the development of mutation was a higher staging score (P = 0.0226). CONCLUSIONS: Both interferon and lamivudine were effective for patients with high ALT levels, but interferon's efficacy appeared to be limited by the degree of fibrosis. Lamivudine appeared to be effective irrespective of the degree of fibrosis, but YMDD mutations seemed to develop sooner in patients with advanced liver fibrosis.

Stromal tumor of the pancreas with expression of c-kit protein: report of a case.

We report on a case of a stromal tumor, similar to a gastrointestinal stromal tumor, originating from the pancreas. The patient was a 54-year-old woman, who was seen at the Kofu Municipal Hospital because of an abdominal tumor. On abdominal computed tomography and splenic arteriography, the tumor was detected in the pancreatic tail. The patient underwent distal pancreatectomy with splenectomy. Macroscopically, the cut surface of the tumor showed almost completely surrounded by the normal pancreatic tissue. Microscopically, the tumor composed of spindle-shaped cells that were immunoreactive for vimentin, CD34, and c-kit protein. Therefore, the tumor was diagnosed as a stromal tumor of the pancreas. The expression of c-kit protein suggests that this pancreatic stromal tumor may originate from primitive mesenchymal cells which can be a logical candidate for the origin of gastrointestinal stromal tumors and extra-gastrointestinal stromal tumors.

Expression of human pendrin in diseased thyroids.

We examined pendrin expression in various diseased thyroid tissues by immunohistochemistry (IHC) using antiserum raised against human pendrin and by real-time quantitative RT-PCR. In normal thyroids the antiserum reacted with the apical membrane of follicular cells and its immunoreactivity was faint. In Graves' thyroids, the IHC expression of pendrin appeared in a pattern similar to that of normal thyroids but it was more extensive and stronger, especially in areas showing marked proliferation of follicular cells. The immunoreactivities of pendrin in nodular goiters varied from case to case. In follicular adenomas, pendrin was localized in the follicle-forming parts of the tumor but was negative in trabecular parts. Pendrin was negative in all follicular carcinomas, papillary carcinomas, and in one case of medullary carcinoma. In quantitive mRNA analysis, the relative values of pendrin mRNA were significantly low in papillary carcinoma (p<0.01), whereas the values in other diseased thyroids were not significantly different from those in normal thyroids. These results suggest that pendrin may play a role in thyroid hormone production as the apical porter of chloride/iodide and investigation of pendrin leads to a better understanding of functional aspects of the iodine transportation system in thyroid diseases.

Macroscopic and microscopic findings of livers in malignant hematologic disorders, biopsied under peritoneoscopy.

It is important to detect liver involvement in extranodal lesions in malignant hematologic disorders to make accurate diagnoses and estimate their clinical stage. We report seven cases of malignant lymphoma and a case of histiocytosis X. All patients expressed positive C-reactive protein and a high erythrocyte sedimentation rate, and a high serum value of alkaline phosphatase or lactic dehydrogenase was seen. Image analyses revealed enlarged livers without any space-occupying lesions. Peritoneoscopy with liver biopsy showed a diffuse presence of white maculae or peliosis hepatis on the liver surface among all the patients, and granulomas with or without malignant cells were observed histologically and congestion was seen in the lobules. Thus, peritoneoscopy with liver biopsy appears to be a useful tool not only to detect early liver involvement in malignant hematologic disorders but also to make their accurate diagnosis.

[Refractory non-small-cell lung cancer responding to combination chemotherapy with gemcitabine and cisplatin].

The patient was a 60-year-old female with adenocarcinoma of the lung. An effective radiation therapy was performed for cervical lymph node metastases found 19 months after the operation. A right adrenal metastasis and abdominal paraaortic lymph node metastases were detected 11 months later, and chemotherapy with cisplatin (CDDP) was administered. Although a temporary partial response was obtained, the metastatic lesion was refractory to CDDP. The patient was treated with gemcitabine (GEM) and CDDP, which resulted in near complete response continued for 3 months. The combination therapy of GEM and CDDP may be effective for recurrent non-small-cell lung cancer refractory to other regimens.

Influence of transfection with connexin 26 gene on malignant potential of human hepatoma cells.

We investigated the effect of transfection with connexin (Cx) 26 gene on the malignant potential of PLC/PRF/5 hepatoma cells, observing changes in their morphological features, alpha-fetoprotein (AFP) expression, cell proliferation and apoptosis in vitro, and their tumor growth in vivo. Fluorescence-activated cell sorting (FACS) analysis showed that 10.6% of PLC/PRF/5 hepatoma cells transfected with Cx26 cDNA expressed excessive Cx26, and the spread of lucifer yellow was wider in the colony of stable transfectants (PLC/Cx26) after its microinjection than in control. Nucleo-cytoplasmic (N/C) ratio was significantly lower in PLC/Cx26 (P < 0.0001). Cell proliferation assay showed significantly lower numbers in PLC/Cx26 on day 10 after seeding than in control (P = 0.0039), and AFP level /10(5) cells was significantly lower in medium of PLC/Cx26 (P = 0.0039). The number of proliferating cell nuclear antigen (PCNA)-positive cells was less in PLC/Cx26 in vitro than in control (P = 0.0039), and single-stranded DNA (ssDNA)-positive cells were more abundant in the colony of PLC/Cx26 (P = 0.029). Tumor volume in SCID mice was significantly smaller in the group of PLC/Cx26 than in the control (P < 0.01) throughout the observation period, and tumor weight of PLC/Cx26 was significantly lower (P = 0.0019) week 9 after inoculation. Transfection with Cx26 cDNA inhibited dedifferentiation, suppressed cell proliferation, and apoptosis was induced. Tumor growth of PLC/Cx26 was retarded. These findings suggest that transfection with Cx26 gene into human hepatoma cells reduces their malignant potential.

Polyethylenimine-mediated suicide gene transfer induces a therapeutic effect for hepatocellular carcinoma in vivo by using an Epstein-Barr virus-based plasmid vector.

The present study aimed to establish a novel efficient nonviral strategy for suicide gene transfer in hepatocellular carcinoma (HCC) in vivo. We employed branched polyethylenimine (PEI) and combined it with Epstein-Barr virus (EBV)-based plasmid vectors. The HCC cells transfected with an EBV-based plasmid carrying the herpes simplex virus-1 thymidine kinase (HSV-1 Tk) gene (pSES.Tk) showed up to 30-fold higher susceptibilities to ganciclovir (GCV) than those transfected with a conventional plasmid vector carrying the HSV-1 Tk gene (pS.Tk). The therapeutic effect in vivo was tested by intratumoral injection of the plasmids into HuH-7 hepatomas transplanted into C.B-17 scid/scid mutant (SCID) mice and subsequent GCV administrations. Treatment with pSES.Tk, but not pS.Tk, markedly suppressed growth of hepatomas in vivo, resulting in a significantly prolonged survival period of the mice. These findings suggest that PEI-mediated gene transfer system can confer efficient expression of the suicide gene in HCC cells in vivo by using EBV-based plasmid vectors.

Immunohistochemical and immunoelectron microscopical localization of procollagen III peptide in papillary carcinoma of thyroid.

The immunohistochemical localization of procollagen III peptide, a precursor of type III collagen, was examined in 38 papillary carcinomas and 25 follicular neoplasms using an immu-noperoxidase technique. Although localization of procollagen ill peptide was not demonstrated in normal follicular cells, distinct cytoplasmic immunostaining of neoplastic cells was frequently found in the tissues examined, as were stromal fibroblasts. Such cytoplasmic immunostaining was observed in 92.1 % of 38 papillary carcinomas and in 36.0% of 25 follicular neoplasms. Cytoplasmic immunoreactivity in papillary carcinomas was more intense at the peripheral zone of the tumor and correlated with the degree of invasiveness. The controls, in which the primary antibody was preabsorbed with procollagen ill peptide or replaced with normal rabbit serum, showed only faint background staining in all specimens. Immunoelectron microscopical examination revealed that electron-dense deposits, indicating procollagen III peptide, were located in the perinuclear space, Golgi apparatus, and rough endoplasmic reticulum of papillary carcinoma cells. These results suggest that neoplastic cells, especially papillary carcinoma cells, could play an important role in type III collagen production, possibly in connection with the creation of an environment that is conducive to their progression.