|Year : 2015 | Volume
| Issue : 3 | Page : 718-724
Hepatocellular carcinoma in Egypt: epidemiological and histopathological properties
Nanis S Holah1, Dina S El-Azab2, Hayam A Aiad1, Dina M Sweed2
1 Department of Pathology, Faculty of Medicine, Menoufia University, Shebin El Kom, Egypt
2 Pathology Department, National Liver Institute, Menoufia University, Shebin El Kom, Egypt
|Date of Submission||06-Feb-2015|
|Date of Acceptance||01-Mar-2015|
|Date of Web Publication||22-Oct-2015|
Dina M Sweed
Pathology Department, National Liver Institute, Menoufia University, 32511 Shebin El Kom
Source of Support: None, Conflict of Interest: None
To study the epidemiological and pathological properties of hepatocellular carcinoma (HCC) cases eligible for surgical resection.
HCC is the sixth most common cancer worldwide and the third most common cause of cancer death. In Egypt, liver cancer forms 1.68% of the total malignancies. HCC constitutes 70.48% of all liver tumors among Egyptians. HCC represents the main complication of cirrhosis.
Materials and methods
This longitudinal study included 92 HCC patients who had undergone surgical intervention. Clinical and demographic data were collected from medical records, and paraffin blocks were retrieved from the Archives of the Pathology Department, National Liver Institute, Menoufia University, during the period between March 2007 and October 2014.
Results revealed that 51.1% of the studied HCC patients were at least 58 years old, 81.5% male and 18.5% female, 51.2% of the patients had an a-fetoprotein level of at least 200 ng/ml and 95.7% were positive for hepatitis viral infection. Revision of the pathological data revealed that 82.6% of the HCC cases presented as a single focal lesion with a median size of 5 cm. About 76.1% were on top of a cirrhotic liver and 44.5% showed dysplastic changes and 96.7% of the cases were of the classic type. About 57.6% of the cases presented with stage T1 and 34.8% of the cases had lymphovascular invasion.
On the basis of 92 surgical specimens of HCC, most of the HCC in Egypt occurred in men who developed a cirrhotic liver due to HCV infection. Epidemiological and histopathological data of HCC highlight the importance of an integrated strategy for the prevention and the treatment of viral hepatitis infections and chronic liver disease.
Keywords: Epidemiology, hepatocellular carcinoma, histopathology
|How to cite this article:|
Holah NS, El-Azab DS, Aiad HA, Sweed DM. Hepatocellular carcinoma in Egypt: epidemiological and histopathological properties. Menoufia Med J 2015;28:718-24
|How to cite this URL:|
Holah NS, El-Azab DS, Aiad HA, Sweed DM. Hepatocellular carcinoma in Egypt: epidemiological and histopathological properties. Menoufia Med J [serial online] 2015 [cited 2018 May 24];28:718-24. Available from: http://www.mmj.eg.net/text.asp?2015/28/3/718/167895
| Introduction|| |
Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy of adults. It is the sixth most common cancer worldwide and the third most common cause of cancer death . In Egypt, liver cancer forms 11.75% of the malignancies of all digestive organs and 1.68% of the total malignancies. HCC constitutes 70.48% of all liver tumors among Egyptians . HCC represents the main complication of cirrhosis, and shows a growing incidence in Egypt, which may be the result of a shift in the relative importance of hepatitis B virus (HBV) and HCV as primary risk factors , and improvements in screening programs and diagnostic tools .
Although most HCC develop in the background of chronic liver disease, some may occur on a normal liver and usually correspond to specific types, including fibrolamellar HCC .
The pathological evaluation of HCC is an overall procedure able to provide its accurate diagnosis and prognosis by evaluating both the macroscopic and the microscopic features of the tumor and aspects of the nontumoral tissue, especially the identification of preneoplastic changes . Therefore, this study aimed to report the epidemiological, clinical, and histopathological properties of HCC patients eligible for surgical intervention, among those who presented at the National liver institute, a tertiary referral center for liver disease in Egypt.
The aim of this study was to investigate the epidemiological and pathological properties of HCC cases eligible for surgical resection.
| Patient and methods|| |
This longitudinal study included 92 liver specimens from HCC patients who had undergone surgery (88 cases of partial hepatectomy and four cases of total hepatectomy from liver transplantation). The required material for the analyses were retrieved from the archival material of the Pathology Department, National Liver Institute, Menoufia University, during the period between March 2007 and October 2014.
The following data were collected: the age, the sex, the a-fetoprotein (a-AFP) level (when available), the presence or the absence of hepatitis viral infection (HCV-RNA and HBV-DNA) by quantitative polymerase chain reaction, and radiologic findings (the tumor focality, the site, and the size).
From each representative paraffin block of the studied cases, 4-μm-thick sections were cut, stained by hematoxylin and eosin (H&E), and re-evaluated to confirm the diagnosis and to assess the following:
(1) The histopathological type (according to the WHO classification of tumors of the digestive system) .
(a) The classical type was divided according to the architectural pattern into the following:
- The trabecular pattern.
- The pseudoglandular (acinar) pattern.
- The compact (solid) pattern.
(b) Other histologic types such as fibrolamellar HCC, schirrous carcinoma, sarcomatoid HCC, and undifferentiated carcinoma.
(2) The tumor grade (according to the WHO classification of tumors of the digestive system) .
- Well differentiated: the lesions are composed of cells with minimal atypia and have an increased nuclear/cytoplasmic (N/C) ratio in a thin trabecular pattern, with frequent pseudoglandular or acinar structures and frequent fatty change.
- Moderately differentiated: they are characterized by tumor cells arranged in trabeculae of three or more cells in thickness. Tumor cells have abundant eosinophilic cytoplasm and round nuclei with distinct nucleoli. A pseudoglandular pattern is also frequent, and pseudoglands frequently contain bile or a proteinaceous fluid.
- Poorly differentiated: they proliferate in a solid pattern without distinct sinusoid-like blood spaces, and only slit-like blood vessels are observed in large tumor nests. Neoplastic cells show an increased N/C ratio and frequent pleomorphism, including bizarre giant cells.
- Undifferentiated lesions constitute solid growth; cells are spindle or round, with little cytoplasm and a high N/C ratio.
(3) The pathological stage [according to the American Joint Committee on Cancer (AJCC) staging system, 7th ed.] .
- Stage I: pT1, solitary tumor without vascular invasion.
- Stage II: pT2, solitary tumor with vascular invasion or multiple tumors, none more than 5 cm.
- Stage IIIA: pT3a, multiple tumors, with one or more greater than 5 cm.
- Stage IIIB: pT3b, solitary tumor or multiple tumors of any size involving a major branch of the portal or the hepatic vein.
- Stage IIIC: pT4, tumor(s) with direct invasion of the adjacent organs other than the gallbladder or with perforation of the visceral peritoneum.
- Stage IVA: any pT, N1: regional lymph node metastasis.
- Stage IVB: any pT, any N, M1: distant metastasis.
(4) Lymphovascular invasion (microscopic invasion): present or absent.
(5) Regional lymph node: the number of involved lymph nodes if submitted.
(6) Adjacent non-neoplastic liver tissue:
- The presence or the absence of cirrhosis: according to the Ishak scoring system, the cirrhotic stage is identified by the presence of variable-sized regenerative parenchymal nodules surrounded by porto-portal and porto-central fibrous links .
- The presence of preneoplastic changes.
- HepPar1 was performed, in cases not confirmed by routine H&E staining, to ensure the hepatocytic origin of the malignant tumor  [Figure 1].
- Immunohistochemical procedures were performed according to standard protocols. HepPar1 antibody (OCH1-E5) is a mouse monoclonal antibody raised against hepatocyte-specific antigens. It was received as a concentrated antibody in a vial contained 100 μg IgG2b in PBS with 0.05% sodium azide (Cat. 94538-6406; Thermo Scientific, Fremont, California, USA), using a dilution of 1 : 50 and the detection kit was ultravision detection system antipoly valent HRP/DAB (ready to use) (cat. #TP-015-HD) (Lab Vision Corporation, Fremont, California, USA).
|Figure 1: A case of hepatocellular carcinoma showing positiv ity for HepPar1 in the form of granular staining of the cytoplasm (immunohistochemical, ×200).|
Click here to view
Data were collected, tabulated, and statistically analyzed in terms of the mean ± SD and percentages using the statistical package for the social science program for windows (version 20; SPSS Inc., Chicago, Illinois, USA).
| Results|| |
Clinicopathological data of the studied HCC cases were as follows [Table 1],[Table 2] and [Table 3]:
(1) The age of the studied cases ranged between 30 and 75 years with 56.22 ± 8.709 as a mean ± SD and 58 years as a median value and 47 patients (51.1%) were at least 58 years old [Table 1].
|Table 1: Epidemiological and laboratory findings of the studied hepatocellular carcinoma cases|
Click here to view
|Table 2: Histopathological findings of the studied hepatocellular carcinoma cases|
Click here to view
|Table 3: Pathological data of the adjacent non-neoplastic liver in the studied hepatocellular carcinoma cases|
Click here to view
(2) Sex: 75 patients (81.5%) were male and 17 patients (18.5%) were female, with 5 : 1 as the male-to-female ratio [Table 1].
(3) Laboratory findings [Table 1]:
(a) The AFP level ranged between 2 and 20 010 ng/ml, with 955.7 ± 3171.78 as the mean ± SD and 200 as the median value with 21/41 cases (51.2%) having a serum value of at least 200 ng/ml.
(b) Etiology: by ELIZA, 88 cases (95.7%) were positive for hepatitis viral infections (91.4% for HCV and 4.3% for HBV).
(4) Macroscopic data [Table 2]:
(a) The tumor focality: 76 cases (82.6%) presented with a single focal lesion [Figure 2] and 16 cases (17.4%) presented with multiple focal lesions [Figure 3].
|Figure 2: A case of hepatoc ellular carcinoma showing a solitary greenish encapsulated mass on the background of a cirrhotic liver.|
Click here to view
|Figure 3: A case of hepatocellular carcinoma showing multiple whitish nodules on the background of a cirrhotic liver.|
Click here to view
(b) The tumor site: in 46 cases (50.0%), the tumor was located in the left lobe, in 41 cases (44.6%), it was located in the right lobe, and in five cases (5.4%), it was located in both the right and the left lobes.
(c) The tumor size: the greatest dimension of the HCC focal lesion ranged between 1 and 20 cm, with 6.21 ± 3.558 as a mean ± SD and 5 cm as a median value.
(5) Microscopic data [Table 2]:
(a) The histopathological type of the tumor: 89/92 of the studied HCC cases (96.7%) were of the classic type, whereas three cases (3.3%) were of the special type (fibrolamellar) [Figure 4].
|Figure 4: A case of fibrolamellar hepatocellular carcinoma showing a fibrous stroma that is composed of bundles of collagen arranged in parallel lamellae (Trichrome stain, ×200).|
Click here to view
(b) The histopathological pattern of classic HCC was as follows: 44 cases (49.4%) exhibited a mixed acinar and trabecular pattern, 25 cases (28.1%) exhibited a trabecular pattern, and 20 cases (22.5%) exhibited a solid pattern.
(c) The grade of classic HCC: 12 cases (13.5%) were well differentiated [Figure 5], 55 cases (61.8%) were moderately differentiated [Figure 6] and [Figure 7], 20 cases (22.5%) were poorly differentiated [Figure 8], and two cases (2.2%) were undifferentiated.
|Figure 5: A case of well-differentiated hepatocellular carcinoma showing a trabecular pattern with very thin trabeculae separated by blood sinusoids (H&E, ×200) .|
Click here to view
|Figure 6: A case of moderately differentiated hepatocellular carcinoma showing bile production in tumor cells and a macrotrabecular pattern (H&E, ×200 ).|
Click here to view
|Figure 7: A case of moderately differentiated hepatocellular carcinoma showing a pseudoglandular pattern with clear cell change (H&E, ×200 ).|
Click here to view
|Figure 8: A case of poorly differentiated hepatocellular carcinoma showing a compact pattern with compressed trabeculae (H&E, ×200).|
Click here to view
(d) The tumor pathologic staging: according to AJCC, 2010, classification of HCC, 53 cases (57.6%) presented with stage T1, 29 cases (31.5%) with stage T2, and 10 cases (10.9%) with stage T3.
(e) Lymphovascular invasion was present in 32/92 of the studied HCC cases (34.8%): 22/32 of these cases (68.8%) had a tumor sized of at least 5 cm, whereas the remaining 10 cases (31.2%) had a tumor sized of less than 5 cm.
(f) Adjacent non-neoplastic liver [Table 3]:
(i) In 70 cases (76.1%), the lesion developed on top of a cirrhotic liver, whereas in 22 cases (23.9%), it developed on top of a noncirrhotic liver; chronic hepatitis [19 cases (20.6%)] or normal liver [three cases (3.3%)].
(ii) About 30/54 (55.5%) of the adjacent non-neoplastic cirrhotic liver cases showed no dysplastic changes, whereas 24 (44.5%) cases showed dysplastic changes (24.1% of the cases with high-grade dysplasia and 20.4% of the cases with low-grade dysplasia).
Note that the studied lymph nodes were available in nine cases only, and they were all negative for malignancy.
| Discussion|| |
HCC represents an important public health problem in Egypt. In many Egyptian regional registries, liver cancer is the first most common cancer in men and the second in women .
The median age of the studied HCC patients was 58 years. This agreed with Baghdady et al. , who reported that the age of the HCC patients ranged between 42 and 70 years (mean 58.70 ± 5.76 years) and also with Shaker et al., who found that the most frequent age category affected by HCC in Egypt was between 51 and 60 years .
The present study showed that 75 of the studied patients (81.5%) were male and 17 patients (18.5%) were female, with a male-to-female ratio of 5 : 1; this was in agreement with a study on the prevalence and the epidemiological features of HCC conducted in Egypt, which included 321 HCC patients, and of them, 82.55% were male, whereas 17.45% were female,  and also with Darbari et al. , who reported that regardless of the geographic location, HCC occurs more frequently in men than in women, with the male : female ratios in various countries ranging from 2 : 1 to 5 : 1. The precise reason is not known, but it has been shown that many tumors have androgen receptors, and there is also a male predominance in risk factors .
Furthermore, serum AFP was available in 41/93 of the HCC cases with a median value of 200 ng/ml, and 51.2% of the valid cases were at least 200 ng/ml, and this agreed with other studies that revealed that serum AFP lacks adequate sensitivity and specificity for the diagnosis of HCC .
Regarding the etiology, the present study revealed that 88 of the HCC cases (95.7%) were positive for hepatitis viral infections (HCV or HBV), of which 91.4% of the cases were associated with HCV infection. This was in agreement with Goldman et al.  who reported that up to 90% of the HCC cases in Egypt were attributable to HCV infection. This high figure was explained by the fact that the rate of HCV in Egypt was the highest in the world, with estimates ranging from 6 to 28% .
Regarding the macroscopic picture, the present study showed that 76 of the HCC cases (82.6%) presented grossly as a single mass and the other 16 cases (17.4%) presented as multiple masses, and they varied in color from white to green according to bile formation, and showed areas of necrosis and hemorrhage, and this agreed with Goodman et al. , who reported that HCC formed an expanding mass well-demarcated from the surrounding liver and varied in color from tan or yellow to grayish-white or, if they produce bile, to green. Tumors that appear encapsulated almost always occurred in a cirrhotic liver .
The present study revealed that HCC cases emerged nearly equal in the left and the right lobes (50.0 and 44.6%, respectively) and only 5.4% of the HCC cases occurred in both lobes. However, 2/3 of the fibrolamellar HCC cases (66.7%) occurred in the left lobe, and this agreed with Goodman et al. , who found that for unknown reasons, two-thirds of the fibrolamellar HCC arise in the left lobe of the liver, and it is the only liver tumor that is more frequent in the left lobe.
Furthermore, the median size of the HCC mass in this study was 5 cm ( mean ± SD=6.21 ± 3.558). This finding agreed with Llovet et al. , who reported that 5 cm was the size that was most likely detected through the surveillance of patients with chronic liver disease and more likely to be resectable than a larger tumor size.
In the current study, 89 HCC cases (96.7%) were of the classic type, whereas only three cases (3.3%) were of the fibrolamellar type. This agreed with the WHO classification of tumors of the liver that reported that fibrolamellar HCC accounted for 0.5-9% of primary liver cancers .
In the present study, we divided HCC cases into four grades on the basis of the worse pattern from well differentiated to undifferentiated according to the WHO classification of tumors of the digestive system . However, different grades were observed in the same mass, in agreement with Pawlik et al. , who reported that grading heterogeneity inside a tumor was frequently observed and may significantly limit the performance of biopsy for grading.
Moreover, the current study revealed that more than half of the cases (57.6%) were presented with stage T1. This may be due to the high association with HCV infection, and this agreed with Schutte et al. , who reported that patients with viral hepatitis showed a trend toward HCC diagnosis at an earlier tumor stage. Also, this could be explained by the selection of cases (eligible for surgical intervention), as surgical intervention is the treatment of choice in patients with early-stage HCC, and this variation was important as the pathological staging was a key to predict the prognosis of patients .
Also, in this study, 68.8% (22/32) of the HCC cases that showed positive vascular invasion had a tumor mass that measured more than 5 cm in size, and this agreed with Pawlik et al. , who found that the incidence of microscopic vascular invasion increased with the tumor size, and microscopic vascular invasion was present in 55% for the patients with tumors measuring 5.1-6.5 cm compared with 31% for all patients with tumors measuring 5 cm or smaller.
Regarding the adjacent non-neoplastic liver, this study showed that 70 HCC cases (76.1%) developed on top of a liver cirrhosis. This could be explained by the etiological factors as most HCC cases associated with hepatitis C, which is the main risk factor, end by the development of cirrhosis . Chronic liver disease leads to cirrhosis, characterized by the formation of regenerative nodules. During this process, genomic instability favors the development of different subtypes of foci of altered hepatocytes, followed by low-grade DNs, high-grade DNs, and subsequently HCC development . Results from this study agreed with Tretiakova et al. , who found that 15-20% of HCC cases mostly associated with chronic HBV infection are reported to arise in noncirrhotic livers.
In the available 54 cirrhotic liver tissue adjacent to HCC cases, 24 of them (44.5%) showed preneoplastic changes [24.1% showed high-grade dysplastic changes (13/54) and 20.4% showed low-grade dysplastic changes (11/54)]. These findings agreed with Tretiakova et al. , who reported that in cirrhosis, HCC developed by a step-wise progression from large regenerative nodules to dysplastic nodules to well-differentiated HCC and subsequently to less differentiated tumors.
The present study included three cases of fibrolamellar variants of HCC (FLC), with a median age of 45 years: 66.7% occurred in men and 66.7% of the cases presented with a single mass. Almost 100% of the FLC cases were negative for hepatitis viral infections and 100% of the adjacent non-neoplastic liver tissue showed normal liver architecture, which agreed with Kakar et al. , who reported that fibrolamellar carcinoma was a variant of HCC with distinct clinicopathologic features. It occurred at a young age and lacked the common risk factors for HCC such as viral hepatitis and cirrhosis as it developed mostly in noncirrhotic livers and has been considered to be less aggressive than conventional HCC .
| Conclusion|| |
On the basis of 92 surgical specimens of HCC, epidemiological and histopathological properties of HCC in our study are comparable to previous global and regional epidemiologic and histopathological studies. The most unique feature is that most of the HCC in Egypt occurred in men who developed a cirrhotic liver due to HCV infection. These results highlight the importance of an integrated strategy for the prevention and the treatment of viral hepatitis infections and chronic liver disease. Also, collection and analysis of epidemiologic and histopathological HCC data play a critical role in guiding future disease prevention strategies and optimizing patient management by providing accurate diagnostic and prognostic data.
| Acknowledgements|| |
Conflicts of interest
There are no conflicts of interest.
| References|| |
Dai L, Ren P, Liu M, Imai H, Tan EM, Zhang JY. Using immunomic approach to enhance tumor-associated autoantibody detection in diagnosis of hepatocellular carcinoma. Clin Immunol 2014; 152
Mokhtar N, Gouda I, Adel I. Cancer pathology registry 2003-2004 and time trend analysis. In: Mokhtar N, Gouda I, Adel I, eds. Malignant digestive system tumors. Cairo: Elsheraa Press; 2007. 55-67.
Gomaa AI, Hashim MS, Waked I. Comparing staging systems for predicting prognosis and survival in patients with hepatocellular carcinoma in Egypt. PLoS One 2014; 9
El-Serag HB. Epidemiology of hepatocellular carcinoma. Clin Liver Dis 2001; 5
Paradis V. Histopathology of hepatocellular carcinoma. Recent Results Cancer Res 2013; 190: 21-32.
Theise N, Park Y, Curado M, et al.
Hepatocellular carcinoma WHO classification of tumors of the digestive System. Lyon: International Agency for Research on Cancer; 2010.
Edge S, Byrd D, Comptom C, Fritz A, Greene F, Trotti A. AJCC cancer staging handbook. New York: Springer; 2010. 237-245.
Ishak K, Baptista A, Bianchi L, Callea F, De Groote J, Gudat F, et al. Histological grading and staging of chronic hepatitis. J Hepatol 1995; 22
Chu PG, Ishizawa S, Wu E, Weiss LM. Hepatocyte antigen as a marker of hepatocellular carcinoma: an immunohistochemical comparison to carcinoembryonic antigen, CD10, and alpha-fetoprotein. Am J Surg Pathol 2002; 26
Baghdady I, Fouad F, Sayed M, et al.
Serum markers for the early detection of hepatocellular carcinoma in patients with chronic viral hepatitis C infection. Menoufia Med J 2014; 27
Shaker MK, Abdella HM, Khalifa MO, El Dorry AK Epidemiological characteristics of hepatocellular carcinoma in Egypt: a retrospective analysis of 1313 cases. Liver Int 2013; 33
Rahman El-Zayadi A, Abaza H, Shawky S, Mohamed MK, Selim OE, Badran HM. Prevalence and epidemiological features of hepatocellular carcinoma in Egypt - a single center experience. Hepatol Res 2001; 19
Darbari A, Sabin KM, Shapiro CN, Schwarz KB. Epidemiology of primary hepatic malignancies in U.S. children. Hepatology 2003; 38
Singal A, Volk ML, Waljee A, Salgia R, Higgins P, Rogers MA, Marrero JA Meta-analysis: surveillance with ultrasound for early-stage hepatocellular carcinoma in patients with cirrhosis. Aliment Pharmacol Ther 2009; 30
Goldman R, Ressom HW, Abdel-Hamid M, Goldman L, Wang A, Varghese RS, et al. Candidate markers for the detection of hepatocellular carcinoma in low-molecular weight fraction of serum. Carcinogenesis 2007; 28
Mohamoud YA, Mumtaz GR, Riome S, Miller D, Abu-Raddad LJ. The epidemiology of hepatitis C virus in Egypt: a systematic review and data synthesis. BMC Infect Dis 2013; 13
Goodman Z, Terracciano L, Wee A. Tumors and tumor-like lesions of the liver. In: Burt A, Portmann B, Ferrell L. eds. MacSween′s pathology of the liver. Churchill Livingstone Elsevier; 2012. 761-851.
Llovet JM, Burroughs A, Bruix J. Hepatocellular carcinoma. Lancet 2003; 362
Pawlik TM, Gleisner AL, Anders RA, Assumpcao L, Maley W, Choti MA. Preoperative assessment of hepatocellular carcinoma tumor grade using needle biopsy: implications for transplant eligibility. Ann Surg 2007; 245
Schütte K, Bornschein J, Kahl S, Seidensticker R, Arend J, Ricke J, Malfertheiner P Delayed diagnosis of HCC with chronic alcoholic liver disease. Liver Cancer 2012; 1
Pons F, Varela M, Llovet JM. Staging systems in hepatocellular carcinoma. HPB (Oxford) 2005; 7
Pawlik TM, Delman KA, Vauthey JN, Nagorney DM, Ng IO, Ikai I, et al. Tumor size predicts vascular invasion and histologic grade: implications for selection of surgical treatment for hepatocellular carcinoma. Liver Transpl 2005; 11
Fattovich G, Stroffolini T, Zagni I, Donato F. Hepatocellular carcinoma in cirrhosis: incidence and risk factors. Gastroenterology 2004; 127
Tretiakova MS, Shabani-Rad MT, Guggisberg K, Hart J, Anders RA, Gao ZH. Genomic and immunophenotypical differences between hepatocellular carcinoma with and without cirrhosis. Histopathology 2010; 56
Kakar S, Burgart LJ, Batts KP, Garcia J, Jain D, Ferrell LD. Clinicopathologic features and survival in fibrolamellar carcinoma: comparison with conventional hepatocellular carcinoma with and without cirrhosis. Mod Pathol 2005; 18
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3]