Abstract P3-10-19: Significance of baseline neutrophil-to-lymphocyte ratio for progression-free survival of patients with HER2-positive locally advanced and metastatic breast cancer treated with trastuzumab emtansine

Purpose The prognosis of human epidermal growth factor receptor 2 (HER2)-positive locally advanced or metastatic breast cancers (MBCs) has dramatically improved due to the introduction of trastuzumab, pertuzumab, and trastuzumab emtansine (T-DM1). The efficacy of T-DM1 is prolonged for some patients; however, the predictive factors remain unknown. There is a report that T-DM1 induced antitumor immunity in patients treated with neoadjuvant therapy, with tumor infiltrating lymphocytes (TILs) increasing after the administration of T-DM1. Based on these observations, the benefits of T-DM1 for prognosis may be mediated by an immune reaction against breast cancers, at least in part. As an indicator of cancer immunity, in addition to TILs, the neutrophil-to-lymphocyte ratio (NLR) has been established in early breast cancers. In the present study, we investigated the usefulness of the NLR for treatment efficacy of T-DM1 in HER2-positive MBCs. Methods Fifty-three advanced or metastatic breast cancers treated with T-DM1 were retrospectively recruited from three institutes. The NLR in the peripheral blood was measured at baseline (just before the start of T-DM1) and after one cycle (just before the start of cycle 2). The cutoff value of the NLR was set at 2.56 (median value) and progression-free survival (PFS) and overall survival (OS) according to NLR levels were evaluated. Results The PFS of patients with NLR-low at baseline (NLR<2.56; n=26; median, not reached) was significantly better than that of patients with NLR-high (NLR≥2.56; n=27; median, 4.13 months; hazard ratio [HR], 0.226; 95% confidence interval [CI], 0.112-0.493; p=0.0001). There was a significant association between improved OS and a low NLR (HR, 0.384; 95% CI, 0.170-0.910; p=0.0296). In the subgroup analysis, patients with NLR-low consistently had improved PFS compared to those with NLR-high irrespective of the number of prior chemotherapy regimens, prior trastuzumab use, visceral metastasis, estrogen receptor status, and HER2 immunohistochemical staining score. According to univariable analysis of each clinical and biological factor for PFS, the NLR-low group was solely and significantly associated with favorable PFS compared with the NLR-high group (HR, 0.226; 95% CI, 0.112-0.493; p=0.0001). The NLR at baseline was significantly decreased (p=0.0010) and lymphocyte count was significantly increased after one cycle treatment (p=0.0005). Interestingly, the PFS of patients whose NLR was high at baseline but changed to low after one cycle (n=12; median PFS, 6.47 months) was better than that of patients with a consistently high NLR (n=14; median PFS, 3.27 months). Conclusion and Discussion A low baseline NLR was found to be significantly associated with improved PFS for patients treated with T-DM1. Interestingly, lymphocyte count was significantly increased in patients in the NLR-low group but not in the NLR-high group after one cycle treatment. Although detailed mechanisms remain unknown, the treatment efficacy of T-DM1 may be partly mediated by immunoreaction on the basis of present data. A low baseline NLR appears to be beneficial for treatment with T-DM1 in HER2-positive breast cancers.

Citation Format: Imamura M, Morimoto T, Egawa C, Miyagawa Y, Miyoshi Y. Significance of baseline neutrophil-to-lymphocyte ratio for progression-free survival of patients with HER2-positive locally advanced and metastatic breast cancer treated with trastuzumab emtansine [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-19.

Abstract P2-09-31: Predictive impact of absolute lymphocyte counts for progression-free survival in HER2-positive advanced breast cancer treated with pertuzumab and trastuzumab plus eribulin or nab-paclitaxel

Background: Tumor-infiltrating lymphocytes might be a one of predictive outcome of human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer (ABC) patients (pts) who treated with trastuzumab and pertuzumab (TP) plus docetaxel. Although peripheral blood-based parameter (PBBP) is reported as a prognostic indicator of patients with early breast cancers, utility of PBBP has not been studied in HER2-positive ABC.

Objective:The aim of our study was to determine whether PBBP is significant for predictive efficacy in HER2-positive ABC treated with TP combined with eribulin (ERI) or nab-paclitaxel (Nab-PTX).

Methods: The 51 patients' data from two single arm phase II trials was included in this retrospective-prospective study; ERI + TP (n=30) or Nab-PTX + TP (n=21) registered with UMIN000012375 or UMIN000006838, respectively. We assessed the PBBP in prospectively collected data and investigated their association with progression-free survival (PFS). In consideration of PBBP, we evaluated absolute lymphocyte count (ALC), neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR). The cutoff values of ALC, NLR, and PLR were set at 1000 cells/μL, 2, and 250, respectively.

Results:Median age at baseline was 58 years (range: 31-77). Median number of previous chemotherapy was 3 (range: 1-10). Pts had multiple metastases, 53% with LNs, 35% with bone, 25% with lung, 20% with liver, and 6% with brain. The objective response rate (CR+PR) and clinical benefit rate (CR+PR+ more than 6 month SD) were 37% (n=19) and 59% (n=30), respectively. The median PFS of all pts was 301 days (range: 21-1281). The PFS of pts with ALC-High was significantly better than those of ALC-low (hazard ratio (HR): 2.74, 95% confidence interval (CI): 1.28 to 5.86; p= .0097). Furthermore, improved PFS was obtained in pts with ALC greater than 1500 cells/μL compared with less than 1000 cells/uL (HR: 4.05, 95% CI: 1.60 to 11.6; p= .0029). Significant associations seem to exist irrespective of number of previous chemotherapy. Since we combined different studies for evaluating PBBP, ERI and Nab-PTX were calculated separately. Marginally significant associations between ALC and PFS were obtained both in ERI (HR: 2.18, 95% CI: 0.87 to 5.60; p=.0973) and Nab-PTX (HR: 3.26, 95% CI: 0.80 to 12.4; p=.0939). The PFS of NLR-low pts was significantly better than those of NLR-high (HR: 2.29, 95% CI: 1.01 to 5.90; p= .0477), but this statistical difference was inferior to those of ALC. There was no significant association between PLR and PFS.

Conclusions: Pre-treatment ALC-High was significantly correlated with favorable PFS of pts treated with TP irrespective of combination chemotherapy in HER2-positve ABC. Prolonged PFS of TP combination therapy might be obtained mediating through host systemic onco-immunity. These data obtained here suggest that a usefulness of ALC for selecting pts who might have clinical benefit from TP combination therapy for heavily treated HER2-positve ABC.

Citation Format: Araki K, Ito Y, Fukada I, Kobayashi K, Ohno S, Miyagawa Y, Imamura M, Kira A, Takatsuka Y, Egawa C, Suwa H, Miyoshi Y. Predictive impact of absolute lymphocyte counts for progression-free survival in HER2-positive advanced breast cancer treated with pertuzumab and trastuzumab plus eribulin or nab-paclitaxel [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-31.

Quantitative analysis of estrogen receptor-alpha and -beta messenger RNA expression in normal and malignant thyroid tissues by real-time polymerase chain reaction

OBJECTIVES

We have conducted a quantitative analysis of estrogen receptor-alpha (ER-alpha) and -beta (ER-beta) mRNA expression in normal thyroid and tumor tissues.

METHODS

Normal thyroid tissues (n = 10) and tumor tissues [(follicular adenoma (n = 14), follicular carcinoma (n = 8), papillary carcinoma (n = 14), anaplastic carcinoma (n = 3) and medullary carcinoma (n = 6)] were obtained at surgery from 45 female patients. ER-alpha and ER-beta mRNA expression has been studied by a quantitative polymerase chain reaction.

RESULTS

ER-alpha mRNA levels in the normal thyroid were not significantly different from those in follicular adenomas, papillary carcinomas and medullary carcinomas but were marginally (p = 0.08) higher than those in follicular and anaplastic carcinomas. ER-beta mRNA levels in the normal thyroid tissues were not significantly different from those in any other tumor tissues. ER-beta to ER-alpha mRNA ratios were significantly (p < 0.05) higher in the normal thyroid tissues than in follicular adenomas. Proportions of ER-beta mRNA variants (ER-beta 1, 2, 5, and 5') did not significantly differ among the normal and tumor tissues.

CONCLUSIONS

A downregulation of ER-alpha mRNA in follicular and anaplastic carcinomas seems to suggest that estrogens are unlikely to play an important role in the carcinogenesis and progression of these carcinomas. On the other hand, a significant decrease in ER-beta to ER-alpha mRNA ratios in follicular adenomas suggests a possible involvement of estrogens in the pathogenesis of this disease since the same phenomenon has been reported on estrogen-dependent breast cancers.

Quantitative analysis of estrogen receptor-alpha and -beta messenger RNA expression in human pancreatic cancers by real-time polymerase chain reaction

Recent studies have disclosed the presence of a second estrogen receptor (ER; ER-beta) in addition to a classical ER-alpha. ER-beta mRNA expression has yet to be studied in pancreatic cancers. Thus, we studied the expression of ER-alpha and ER-beta mRNA in pancreatic cancers (n=29) by real-time quantitative reverse transcriptase-polymerase chain reaction, and compared the expression levels in pancreatic cancers with those in breast cancers (n=116) which are typical estrogen-dependent tumors. Breast cancers were divided into two groups, ER-positive and ER-negative, according to the ER status determined by enzyme immunoassay. ER-alpha mRNA levels were significantly (P<0.01) higher in ER-positive (679.4+/-74.7 fmol/microg RNA) than ER-negative (159.7+/-33.4) breast cancers, and pancreatic cancers showed significantly (P<0.01) lower ER-alpha mRNA levels (17.5+/-10.0) than ER-negative breast cancers. On the other hand, ER-beta mRNA levels were significantly (P<0.01) higher in ER-negative (14.1+/-1.6) than ER-positive breast cancers (7.9+/-1.0), and pancreatic cancers showed significantly (P<0.01) higher ER-beta mRNA levels (28.1+/-5.1) than ER-negative breast cancers. Accordingly, ER-alpha/ER-beta mRNA ratios were significantly (P<0.01) lower in pancreatic cancers (0.94+/-053) than in ER-positive (203.9+/-34.5) and ER-negative (21.9+/-5.2) breast cancers. ER-beta2 mRNA variant expression was significantly (P<0.05) higher in pancreatic cancers than in ER-positive and ER-negative breast cancers, and, on the contrary, ER-beta1 mRNA variant expression was significantly (P<0.01) lower in pancreatic cancers than in ER-positive and ER-negative breast cancers. These results suggest a possibility that ER-beta (ER-beta2) plays a more important role than ER-alpha in pancreatic cancers.

Decreased expression of BRCA2 mRNA predicts favorable response to docetaxel in breast cancer

The clinical usefulness of BRCA1 and BRCA2 mRNA levels in tumor tissues in the prediction of response to docetaxel (DOC) treatment has been studied in breast-cancer patients. Twenty-five patients with locally advanced breast tumors (n = 13) or locally recurrent tumors (n = 12) underwent tumor biopsy and were treated with DOC (60 mg/m2 every 3 weeks). BRCA1 and BRCA2 mRNA levels in the tumors were determined by real-time PCR, and the expression of 6 biological markers (P-glycoprotein, p53, erbB2, BCL2, MIB1, estrogen receptor-alpha) in the tumors was determined by immunohistochemistry. BRCA2 mRNA levels (0.547 +/- 0.200, mean +/- SE) of responders to DOC treatment were significantly (p < 0.05) lower than those of non-responders (1.538 +/- 0.358), but there was no significant difference in BRCA1 mRNA levels between responders (0.389 +/- 0.081) and non-responders (0.779 +/- 0.172). Tumors were dichotomized into groups with high or low BRCA2 mRNA levels according to the cut-off value of 0.13. The response rate (25%) of tumors with high BRCA2 mRNA levels was significantly (p < 0.01) lower than that (100%) of tumors with low BRCA2 mRNA levels. Positive predictive value, negative predictive value and diagnostic accuracy of the BRCA2 mRNA assay in the prediction of response to DOC were 100%, 75% and 80%, respectively. No significant difference was found between responders and non-responders in the expression status of any of the other 6 biological markers. These results suggest that BRCA2 mRNA levels in tumor tissues might be clinically useful in the prediction of response to DOC treatment in breast-cancer patients.

Quantitative analysis of BRCA1 and BRCA2 mRNA expression in sporadic breast carcinomas and its relationship with clinicopathological characteristics

BRCA1 and BRCA2 mRNA expression in sporadic breast cancers was quantified by a real-time reverse transcriptase-polymerase chain reaction (RT-PCR), and the relationship of their expression with various clinicopathological factors was studied. BRCA2 mRNA levels (0.993 +/- 1.395, mean +/- SD (BRCA2 / beta-glucuronidase mRNA ratios)) were significantly (P < 0.01) higher than BRCA1 mRNA levels (0.519 +/- 0.570 (BRCA1 / beta-glucuronidase mRNA ratios)), and a weak but significant (r = 0.390, P < 0.01) correlation was observed between BRCA1 and BRCA2 mRNA expression levels. There was no significant association between BRCA1 mRNA expression and clinicopathological factors such as menstrual status, tumor size, lymph node status, estrogen and progesterone receptor status, and histological grade. On the other hand, there was a significant association between higher BRCA2 mRNA expression and estrogen receptor (ER) negativity (P < 0.01) or progesterone receptor (PR) negativity (P < 0.01) or high histological grade (P < 0.01). These results suggest a differential contribution of BRCA1 and BRCA2 in the pathogenesis of sporadic breast cancers. BRCA2 mRNA is speculated to be up-regulated in response to proliferation and genomic instability in high histological grade tumors.

Association of centrosomal kinase STK15/BTAK mRNA expression with chromosomal instability in human breast cancers

Over-expression of a centrosomal serine/threonine kinase, STK15/BTAK, induces centrosome amplification, which results in chromosomal instability (CIN) in cell culture. In the present study, we investigated the correlation of STK15/BTAK mRNA expression with CIN and various clinicopathological factors in human breast cancer. STK15/BTAK mRNA levels were quantified by real-time PCR, and CIN values were determined by FISH analysis of chromosomes 1, 11 and 17 using centromeric probes. STK15/BTAK mRNA levels (0.310 +/- 0.413, mean +/- SD, n = 47) in breast cancers were significantly (p < 0.01) higher than those in normal breast tissues (0.044 +/- 0.029, n = 9). Furthermore, breast cancers were divided into 3 groups (low, intermediate and high) according to STK15/BTAK mRNA expression levels. CIN values of the low-expression group (27.9 +/- 12.6%, n = 18) were significantly (p < 0.01) higher than those of normal breast tissues (9.2 +/- 2.6%, n = 6), and those of the high-expression group (38.0 +/- 12.7%, n = 14) were significantly (p < 0.05) higher than those of the low-expression group. STK15/BTAK mRNA expression showed a significant (p < 0.05) correlation with high histological grade and negativity of estrogen and progesterone receptors. Our results demonstrate that STK15/BTAK mRNA is over-expressed in the majority of breast cancers and its over-expression is significantly associated with CIN, implicating STK15/BTAK in carcinogenesis through induction of CIN. STK15/BTAK mRNA levels might be useful as an indicator of poor prognosis and resistance to endocrine therapy.

Clinicopathologic analysis of breast carcinoma with chromosomal aneusomy detected by fluorescence in situ hybridization

BACKGROUND

The clinicopathologic characteristics of breast carcinoma with chromosomal aneusomy detected by fluorescence in situ hybridization (FISH) have yet to be clarified.

METHODS

Fine-needle aspiration biopsy (FNAB) samples were obtained from 113 breast tumors and were subjected to FISH analysis using centromeric probes for chromosomes 1, 11, and 17 to study a numerical aberration of these chromosomes and its correlation with various clinicopathologic features of breast tumors.

RESULTS

Polysomy was observed in 77.0%, 50.5%, and 37.2% of breast carcinoma samples for chromosomes 1, 11, and 17, respectively, and monosomy was observed in 1.8%, 8.8%, and 22.1% for chromosomes 1, 11, and 17, respectively. High histologic grade showed a significant correlation (P < 0.05) with polysomy of chromosome 11. Lymph node metastasis showed a significant correlation (P < 0.05) with polysomy of all three chromosomes, and positivity of lymph node metastasis increased as the number of polysomic chromosomes increased. In addition, estrogen receptor negativity was correlated significantly (P < 0.05) with monosomy of chromosome 17, and progesterone receptor negativity was correlated significantly (P < 0.05) with polysomy of chromosomes 11 and 17.

CONCLUSIONS

Aneusomy of chromosome 1, 11, or 17 detected by FISH is correlated significantly with various clinicopathologic features of breast carcinoma. Because FISH analysis of chromosomal aneusomy can be done using FNAB samples, this technique seems to have the potential to be used for a better, preoperative definition of the biologic characteristics of breast tumors.

Quantitative analysis of estrogen receptor-beta mRNA and its variants in human breast cancers

We have carried out a quantitative analysis of ER-alpha and ER-beta mRNA expression in normal (n = 11) and breast cancer (n = 112) tissues using a real-time (Taq-Man) PCR assay. Expression of ER-beta mRNA variants has also been studied by triple-primer PCR assay. ER-alpha mRNA levels in normal breast tissues were significantly (p < 0.01) lower than those in ER-positive breast cancers but not significantly different from those in ER-negative breast cancers. However, ER-beta mRNA levels in normal breast tissues were significantly (p < 0.01) higher than those in ER-positive and ER-negative breast cancers. Proportions of ER-beta1 and ER-beta2 mRNA expression among total ER-beta mRNA expression were significantly higher and those of ER-beta5 and ER-beta5; mRNA were significantly lower in normal breast tissues than in ER-positive and ER-negative breast cancers. ER-beta mRNA levels and proportions of ER-beta mRNA variants did not show any significant correlation with age, tumor size, lymph node status and histological grade. Our results demonstrate that ER-alpha mRNA is up-regulated and ER-beta mRNA is down-regulated during carcinogenesis of breast cancers. Changes in proportions of ER-beta mRNA variants are also implicated in this process.

Genetic polymorphism in CYP17 and breast cancer risk in Japanese women

A case-control study was conducted to investigate the association of two genetic polymorphisms (1931T/C and 1951G/A) in the promoter region of the CYP17 gene with breast cancer risk in Japanese women. No significant association was observed between CYP17 polymorphism(1951G/A) and breast cancer risk (odds ratio (OR) = 1.71, 95% confidence interval (CI): 0.28-1.84). In contrast, a significant increase in breast cancer risk (OR= 1.82. 95% CI: 1.07-3.12) was observed in CYP17(1931C/C) homozygotes compared with CYP17(1931T/C) heterozygotes and CYP17(1931T/T) homozygotes when women aged > or = 55 years were considered, but such a significant increase was not observed when women aged < or = 54 years were considered (OR = 0.96, 95% CI: 0.56-1.63). These results suggest that CYP17 polymorphism(1931T/C) would be useful in the selection of Japanese women at a high risk for developing breast cancer at the age of > or = 55 years.

Acceleration of chromosomal instability by loss of BRCA1 expression and p53 abnormality in sporadic breast cancers

Correlation of chromosomal instability (CIN) with BRCA1 expression and p53 abnormality was studied in sporadic breast cancers since these genes are implicated in the double strand DNA repair and mitotic checkpoint, and loss of their function is speculated to result in the accumulation of CIN. CIN values (percentage of cells with non-modal chromosomes) were determined by fluorescence in situ hybridization of chromosomes 1, 11, and 17. BRCA1 expression was studied by immunostaining, and p53 abnormality was studied by immunostaining and polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP). CIN values of BRCA1 negative/p53 normal tumors (28.9+/-13.8, n=23) and those of BRCA1 positive/p53 abnormal tumors (27.0+/-2.3, n=3) were not significantly different from those of BRCA1 positive/p53 normal tumors (23.8+/-11.5, n=10). On the other hand, BRCA1 negative/p53 abnormal tumors (41.2+/-12.7, n=23) showed a significant (P<0.01) increase in CIN values than BRCA1 positive/p53 normal tumors. There was no significant association between CIN values and menopausal status, tumor size, histological grade, lymph node status, or estrogen receptor status. These results suggest that BRCA1 down-regulation and p53 abnormality work synergistically to induce CIN in breast cancers, and that clinico-pathological characteristics of breast cancers with high CIN still remain to be established.

Quantitative analysis of estrogen receptor-alpha and -beta messenger RNA expression in breast carcinoma by real-time polymerase chain reaction

BACKGROUND

Estrogen action is mediated not only through a classic estrogen receptor (ER) (ER-alpha) but also through a second ER (ER-beta) that has a structure and function similar to ER-alpha. A correlation between ER-beta mRNA expression with ER and progesterone receptor (PR) protein levels as well as prognostic factors remains to be established in breast carcinoma.

METHODS

The authors conducted a quantitative analysis of ER-alpha and ER-beta mRNA expression in 116 breast tumors using real-time polymerase chain reaction (PCR), and investigated a possible correlation between ER-alpha and ER-beta mRNA expression and ER and PR status as determined by enzyme immunoassay as well as with various prognostic factors.

RESULTS

ER-alpha mRNA levels were significantly (P < 0.01) higher in ER positive compared with ER negative tumors. Conversely, ER-beta mRNA levels were significantly (P < 0.01) lower in ER positive compared with ER negative tumors. Accordingly, the ratio of ER-beta to ER-alpha was significantly (P < 0.01) higher in ER negative compared with ER positive tumors. A subset analysis based on ER and PR status showed that ER-beta mRNA levels as well as the ratios of ER-beta to ER-alpha mRNA level were highest in ER negative and PR negative tumors (P < 0.05). ER-alpha mRNA levels were significantly (P < 0.05) higher in postmenopausal compared with premenopausal tumors. Histologic Grade 3 tumors showed a significant decrease in ER-alpha mRNA levels compared with Grade 1 and 2 tumors (P < 0.01 and P < 0.05, respectively). No significant correlation between ER-alpha and ER-beta mRNA levels and histologic type, tumor size, or lymph node status was observed.

CONCLUSIONS

An absolute and relative increase in ER-beta mRNA levels in ER negative and PR negative breast tumors, which rarely respond to endocrine therapy, suggests the possible involvement of up-regulation of ER-beta mRNA in the development of estrogen-independent tumors.

Breast cancer risk associated with polymorphism in CYP19 in Japanese women

Screening of the entire coding and major promoter regions of the CYP19 gene identified two novel polymorphisms at codon 39 (Trp to Arg) and codon 408 (silent) in addition to those reported previously at codon 264 (Arg to Cys) and intron 4 [tetranucleotide (TTTA) simple tandem repeat]. A case-control study was conducted in order to see whether or not these polymorphisms were associated with breast cancer risk in Japanese women. Homozygous and heterozygous carriers of the variant allele Arg at codon 39 showed a significantly decreased risk of breast cancer (OR=0.39, 95%C.I.=0. 17-0.89). On the other hand, homozygous carriers of the allele with 10 or more TTTA repeats at intron 4 showed a trend toward an increase (OR=1.80, 95%C.I.=0.97-3.36) in breast cancer risk. Other polymorphisms were found not to be associated with breast cancer risk. These results suggest that the CYP19 polymorphisms at exon 39 and intron 4 would be useful for selecting Japanese women at a high risk of breast cancer.

Innervation of the chicken parathyroid glands: immunohistochemical study with the TuJ1, galanin, VIP, substance P, CGRP and tyrosine hydroxylase antibodies

The innervation of the chicken parathyroid glands was studied by immunohistochemistry using various antibodies. The parathyroid glands, as well as the carotid body and ultimobranchial gland, received branches originating from the vagus nerve. Numerous nerve fibers immunolabeled with the monoclonal antibody (TuJ1) against neuron-specific class III beta-tubulin isotype were found in the connective tissue capsule and septa penetrating into the parathyroid parenchyma. They were also prominent in the wall of blood vessels. Peptidergic nerve fibers immunoreactive for galanin, vasoactive intestinal polypeptide (VIP), substance P and calcitonin gene-related peptide (CGRP) were densely distributed in the capsule, septa and blood vessel walls of the parathyroid glands. In addition, some TuJ1-, substance P- and CGRP-immunoreactive fibers were detected in close association with the parenchymal cells of parathyroid glands. Tyrosine hydroxylase-immunoreactive fibers were concentrated around blood vessels and also in connective tissue stroma.