Cancer Detection and Prevention

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Quantitative assessment of red meat or processed meat consumption and kidney cancer

Dominik D. Alexander, Colleen A. Cushing

Abstract: Objective: To conduct a quantitative assessment of red meat or processed meat consumption and kidney cancer. Methods: We extracted data from 12 case–control studies, three cohort studies, and the Pooling Project of Diet and Cancer publication for which 13 international cohorts were evaluated. Random effects meta-analysis models were used to calculate summary relative risk estimates (SRRE) based on high vs. low intake values. Sensitivity and influence analyses were conducted, including assessments of heterogeneity. Results: The SRRE for all studies that reported results for red meat (included variables labeled ‘red meat’ or single red meat items, such as beef, pork, or liver) was 1.12 (95% CI: 0.98–1.29; p-value for heterogeneity=0.015), and the SRRE using only data from prospective cohorts was 1.02 (95% CI: 0.91–1.15) with minimal heterogeneity (p=0.741). Similarly, in a meta-analysis of the five studies that simultaneously adjusted for smoking, BMI, and total energy intake, the SRRE for red meat was 1.02 (95% CI: 0.91–1.15). No significant association was observed in the meta-analysis of processed meat consumption (SRRE=1.07; 95% CI: 0.94–1.23), although a significant association was observed when only data from cohort studies were analyzed (SRRE=1.19; 95% CI: 1.03–1.37). Conclusions: Although many of the summary results were positive, all were weak in magnitude, most were not statistically significant, and associations were attenuated among studies that adjusted for key potential confounding factors. In summary, the findings of this meta-analysis are not supportive of an independent relation between red or processed meat intake and kidney cancer.

Lifetime consumption of alcoholic beverages and risk of 13 types of cancer in men: Results from a case–control study in Montreal

Andrea Benedetti, Marie-Elise Parent, Jack Siemiatycki

Abstract: Background: The aim of the study was to investigate the association between lifetime consumption of alcoholic beverages and cancer risk. Methods: Data were collected in a population-based case–control study, conducted in Montreal in the mid-1980s, designed to assess the associations between hundreds of non-occupational and occupational exposures and multiple cancer sites in men. We present results for 13 cancer sites: oesophagus (n=78), stomach (n=215), colon (n=427), rectum (n=239), liver (n=28), pancreas (n=83), lung (n=700), melanoma (n=107), prostate (n=374), bladder (n=425), kidney (n=156), Hodgkin's lymphoma (n=42), and non-Hodgkin's lymphoma (n=190), in comparison to population controls (n=507). Odds ratios (OR) were estimated for the associations between lifetime consumption of total alcoholic beverages, beer, wine, and/or spirits, altogether and separately, and each cancer site, while carefully adjusting for smoking and other covariates using polytomous logistic regression. Results: For several cancers (oesophagus, stomach, colon, liver, pancreas, lung, prostate) there was evidence of increased risk among alcohol consumers compared with abstainers and occasional drinkers. For most sites, it was beer and to a lesser extent spirits consumption that drove the excess risks. Conclusions: Our results support the hypothesis that moderate and high alcohol intake levels over the lifetime might increase cancer risk at several sites.

Epidemiology of primary brain tumors in the Middle Eastern population in California, USA 2001–2005

Kiumarss Nasseri, John R. Mills

Abstract: Background: The fast growing Middle Eastern (ME) population has rarely been studied in the U.S.. The purpose of this study was to compare the epidemiology of primary brain tumors in this ethnic population with the non-Hispanic, non-Middle Eastern White (NHNMW) in California. Methods: ME cases were identified by surname in the California cancer registry and ME population estimates were based on ancestry. Data for 683 cases of primary brain tumors (429 benign, 238 malignant, 16 uncertain) in the ME and 15,589 cases (8352 benign, 6812 malignant, 425 uncertain) in the NHNMW were available for this study. Results: ME patients were significantly (p<0.05) younger and their age-adjusted incidence rates per 100,000 for benign tumors of 10.0 in men and 17.6 in women were higher than similar rates of 7.3 and 10.6 in the NHNMW group (p<0.05). Rates for malignant tumors were similar. Meningioma was the main histology responsible for the observed increase in patients over 40 years of age. Also increased were benign tumors of the pituitary and pineal glands. The overall mortality in patients with benign tumors was significantly lower than malignant tumors. Conclusions: This study presents a significantly high incidence of benign meningioma in the ME population in California. This may be due to higher susceptibility or exposure of this ethnic group to the risk factor(s) for this neoplasm. Considering the reported causal association of benign meningioma with childhood radiation exposure from Israel, exposure to this risk factor in this ethnic group needs to be evaluated in future studies.

Cervical cancer screening in medically underserved California Latina and non-Latina women: Effect of age and regularity of Pap testing

Lydia Pleotis Howell, Sunitha Gurusinghe, Farzaneh Tabnak, Stan Sciortino

Abstract: Background: This study focuses on age, race/ethnicity and regular cervical cancer screening of medically underserved Latina and non-Latina women enrolled in California's Cancer Detection Programs: Every Woman Counts (CDP: EWC). Methods: Data from a cohort of women were evaluated for regularity of screening and ethnicity utilizing multi-category logistic regression models to investigate Pap test and biopsy results. Results: There was no statistically significant difference among medically underserved Latina or non-Latina women in Pap test result and stage of cervical cancer after controlling for age and screening regularity. Rarely/never Pap-tested women were more likely to have ‘SIL/ASC’ (odds ratio=1.19; 95% confidence interval=1.08, 1.31) compared to women who were screened regularly. Medically underserved 25–39-year-old women were also more likely to be identified with ‘SIL/ASC’ (odds ratio=1.64; 95% confidence interval=1.50, 1.79) than women 50 and over. Younger were more likely to have low-grade ‘HPV/Condylomata, Atypia/CINI/LSIL’ (odds ratio=2.48; 95% confidence interval=1.66, 3.72) and high-grade ‘CIN II/III/HSIL/CI/Other Cancers’ (odds ratio=1.53; 95% confidence interval=1.08, 2.16) than women age 40 and above, similar to rarely/never Pap-tested women. Conclusions: Women were more likely to be identified with high-grade precancerous cervical lesions and cancer process when they did not have regular screening, Ethnic differences in screening outcomes seem to be minimized by participation in a program that provides consistent screening resources to the medically underserved women who enroll. These findings support prevention strategies that expand screening to all medically underserved younger women or that provide HPV vaccination at an early age.

MDM2 SNP309T>G polymorphism and risk of hepatocellular carcinoma: A case–control analysis in a Moroccan population

Abstract: Background: The Murine double minute 2 (MDM2) gene encodes a negative regulator of the p53 tumor suppressor protein. A single nucleotide polymorphism (SNP) in the MDM2 promoter (a T to G exchange at nucleotide 309) has been reported to produce accelerated tumor formation. The aim of this study was to investigate whether this functional SNP is associated with an enhanced risk of liver tumorigenesis in Moroccan patients. Methods: The study consisted in the comparison of 96 hepatocellular carcinomas (HCC) cases and 222 controls without HCC matched for age, gender and ethnicity. PCR–RFLP and sequencing methods were used to determine the genotype at the MDM2 SNP309T>G locus. Results: Overall, our results indicate that the GG genotype of SNP309 is significantly associated with an increased risk of HCC (odds ratio, OR=2.60, 95% CI, 1.08–6.28). Interestingly, despite a wide range of confidence interval, there is a trend associating the GG genotype with a high risk of HCC in males (OR=3.31; 95% CI, 0.93–11.82) and in HCV-infected patients (OR=3.7; 95% CI, 0.82–16.45). By contrast, no association between age at diagnosis and MDM2 SNP309 genotypes was observed in HCC patients (P=0.610). Conclusion: Our findings suggest that the MDM2 309T>G polymorphism is an important modulator of hepatocellular carcinoma development in Moroccan patients.

Vitamin D receptor gene polymorphism(s) and breast cancer risk in north Indians

Abstract: Background: Vitamin D (1,25-dihydroxyVitamin D3) has shown experimentally anticarcinogenic effects and is thought to protect against breast cancer. The actions of Vitamin D are mediated via the Vitamin D receptor (VDR), and the polymorphisms at 3′UTR region of this gene are associated with the risk and progression of breast carcinoma. The current study is an attempt to examine the association of these variations with breast cancer risk in north Indians. Methods: A total of 160 cases and 140 control subjects were studied for the polymorphisms at 3′ end of the VDR gene. A polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) method and fragment analysis was performed to determine ApaI and TaqI polymorphisms and variable length poly-A microsatellite repeats. Linkage disequilibrium (LD) was calculated for each pair of polymorphisms. Unadjusted and adjusted odds ratios for breast cancer with genotypes comprising the polymorphic sites were calculated to understand their role towards breast cancer susceptibility. Results: Patient's with long poly-A repeat showed a significant association with disease (χ2=9.52, df=2, P≤0.01). Compared to subjects having two S alleles (SS), odds ratios (and 95% CI) were 0.75 (0.45–1.23) and 2.49 (1.18–5.27) for subjects having genotypes SL and LL, respectively. Among matched pairs (age), the poly-A LL genotype was found significantly associated with increased risk of breast cancer among early-onset cases (P=0.02). The unconditional logistic regression analysis demonstrated a significant association between grade and LL genotype [(unadjusted odds ratio (95% CI): 4.45 (1.87, 10.63); adjusted odds ratio: 4.66 (1.88, 11.53)]. No significant association was observed for the VDR ApaI (χ2=1.00, df=2, P=0.60) and TaqI polymorphism (χ2=0.35, df=2, P=0.83). Although, strong LD was not observed among these polymorphic sites, it denies the total equilibrium at the same time. Based on haplotype distribution, the most common one observed among cases and controls was ATS while, genotype AATTLL had shown a significant association with the breast cancer risk (P=0.02). Conclusions: The results indicate that the VDR poly-A polymorphism is significantly associated with breast cancer risk in north Indians especially with early onset disease. Although, ApaI and TaqI did not show any significant association with the disease when analyzed in isolation, but TaqI might modulate the risk associated with L alleles. Further, understanding the functional role of these variants residing on the VDR haplotype associated with disease susceptibility may suggest novel approaches for breast cancer prevention and therapy.

Combined effect of NAT2, MTR and MTHFR genotypes and tobacco on bladder cancer susceptibility in Tunisian population

Abstract: Background: Cigarette smoking is the predominant risk factor for bladder cancer. This risk may be modified by polymorphisms in carcinogens metabolism genes; including those involving the N-acetyl transferase 2 (NAT2) which have been correlated with decreased enzyme activities. Moreover, folate insufficiency can induces carcinogenesis by decreasing DNA methylation. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) are enzymes that play central roles in the folate metabolic pathway. The MTHFR 677*T and MTR 2756*G variants are associated with decreased enzyme activity. Methods: In this work, we have conducted a case-control study in order to assess the combined effect of tobacco, slow NAT2 variants, MTHFR 677*T and MTR 2756*G alleles on bladder cancer development in North Tunisia. Results: For MTR A2756G, alleles and genotypic distributions differed significantly between cases and controls (p=0.00009, OR=3.27, CI 95% 1.76–6.12). While, in non-smokers patients the slow NAT2 did not appear to influence bladder cancer susceptibility; our results suggested that it might act with an additive contribution with tobacco as well as with that determined by MTR 2756 AG or 2756 GG genotypes (p=0.0008). Identical cumulative effect was detected for slow NAT2 and MTHFR 677*T variant (p=0.0003; OR=36.6; CI 95% 3.4–935.3). Conclusion: The strongest result obtained by this study was for an additive effect between smoking status, slow NAT2 variants, MTR 2756*G and MTHFR 677*T alleles, in affecting bladder cancer risk.

Haplotype-tagging single nucleotide polymorphisms in the GSTP1 gene promoter and susceptibility to lung cancer

Xiang-Lin Tan, Roxana Moslehi, WeiGuo Han, Simon D. Spivack

Abstract: Background: Glutathione S-transferase (GST) P1 is a major phase II xenobiotic-metabolizing enzyme in the human lung. Our laboratory had previously identified nine single nucleotide polymorphisms (SNPs) in the GSTP1 gene promoter, which were then grouped into three main haplotypes (Hap1, Hap2, and Hap3) based on statistical inference. Hap3 was found to display a high expression phenotype. The main objective of the current study was to test the association between GSTP1 promoter haplotypes with the risk of lung cancer after determining the promoter haplotypes experimentally through cloning and sequencing. Methods: We conducted a case–control analysis of 150 subjects with lung cancer and 329 controls with no personal history of the disease. The three statistically inferred GSTP1 promoter haplotypes were confirmed experimentally through cloning and sequencing. Haplotype-tagging SNPs were selected and GSTP1 haplotypes were tested for genetic association to lung cancer using unconditional logistic regression after adjusting for confounders. Statistical interaction between GSTP1 promoter haplotypes with either cigarette smoking or dietary fruit and vegetable intake were tested using the likelihood ratio test. Results: We did not find protective effects of Hap3 against lung cancer, despite an adequately powered design for this main effect. Homozygous variants of tagSNPs −1738 T>A and −354 G>T, which tag Hap2, showed an increased (but statistically non-significant) risk of lung cancer among all subjects as well as among individuals with low fruit and vegetable intake, compared to homozygous wildtypes for these SNPs. We did not find significant interactions between Hap2 and dietary intake of fruits and vegetables. Conclusions: Our results do not support significant main and modifying effects for GSTP1 promoter haplotypes on susceptibility to lung cancer in this population, but reinforce the protective effects of dietary intake of fruits and vegetables.

Association of NAT2, GSTM1, GSTT1, CYP2A6, and CYP2A13 gene polymorphisms with susceptibility and clinicopathologic characteristics of bladder cancer in Central China

Abstract: Objective: To explore the association of polymorphisms in N-acetyltransferase 2 (NAT2), glutathione S-transferase (GST), cytochrome P450 (CYP) 2A6, and CYP 2A13 genes with susceptibility and clinicopathologic characteristics of bladder cancer in a Chinese population. Methods: In a hospital-based case-control study of 208 cases and 212 controls matched on age and gender, genotypes were determined by PCR-based methods. Risks were evaluated by unconditional logistic regression analysis. Results: It was found that significant associations of the NAT2 slow-acetylator genotype (odds ratio, OR: 2.42; 95% confidence interval, CI: 1.47–3.99), GSTM1 null genotype (OR: 1.64; 95% CI: 1.11–2.42) and GSTM1/GSTT1-double null genotype (OR: 1.72; 95% CI: 1.00–2.95) with increased risk of bladder cancer. Conversely, carriers with at least one CYP2A6*4 allele showed lower risk than the non-carriers (OR: 0.47; 95% CI: 0.28–0.79). The adjusted ORs (95% CI) for smokers with NAT2 slow-acetylator, GSTM1 null, GSTM1/GSTT1-double null genotype, and variant CYP2A6 genotypes were 2.99 (1.44–6.25), 1.98 (1.13–3.48), 2.66 (1.22–5.81) and 0.41 (0.20–0.86), respectively. Furthermore, NAT2 slow-acetylator, GSTM1 null, and GSTM1/GSTT1-double null genotypes were associated with higher tumor grade (P=0.001, 0.022, and 0.036, respectively), and only NAT2 slow-acetylator genotype was associated with higher tumor stage (P=0.007). CYP2A13 was not associated with risk or tumor characteristics. Conclusion: It is suggested that NAT2 slow-acetylator, GSTM1 null, GSTM1/GSTT1-double null, and variant CYP2A6 genotypes may play important roles in the development of bladder cancer in Henan area, China.

A deficit in biopsying potentially premalignant oral lesions in Puerto Rico

Abstract: Background: Intraoral lesions clinically suspicious for cancer/precancer should be biopsied and diagnosed histopathologically. We evaluated whether the frequency of oral cancer (OC) cases diagnosed in Puerto Rico (PR) is disproportionately high relative to the frequency of persons with histopathologic diagnoses that would have appeared clinically suspicious for OC/precancer at biopsy. Methods: All pathology reports for oral (ICD-O-3 C01-C06) soft tissue biopsies generated during 1/2004–5/2005 by seven PR and two New York City (NYC) pathology laboratories were reviewed. The analysis was restricted to persons diagnosed with invasive oral squamous cell carcinoma (OSCC), epithelial dysplasia, or hyperkeratosis/epithelial hyperplasia (HK/EH), i.e., diagnoses associated with lesions clinically suspicious for OC/precancer. The OC relative frequency measured the percentage of persons diagnosed with OSCC among persons with OSCC, dysplasia, or HK/EH. OC relative frequencies for PR and NYC laboratories were compared. Results: Overall, the OC relative frequency was 67% in PR and 40% and 4% in the NYC general and oral pathology laboratories, respectively (each p<0.001). In PR, the OC relative frequency was highest for males (80%). When OC relative frequencies were stratified by pathology laboratory type (general/oral) and compared across PR and NYC, age/gender-specific OC relative frequencies were always higher in PR; however, differences were consistently statistically significant for males only. Conclusion: A disparity in the OC relative frequency exists in PR vs. NYC indicating a shortfall in biopsying potentially precancerous oral lesions in PR. PR residents with intraoral lesions suspicious for oral cancer/precancer are most likely to be biopsied only after developing an invasive OC.

Specific thermographic changes during Walker 256 carcinoma development: Differential infrared imaging of tumour, inflammation and haematoma

Abstract: Background: Infrared imaging measures spatial variations in the skin temperature aiming to determine pathological processes; hence possible use of this non-invasive analytical method in cancer detection is emerging. Methods: Infrared thermal imaging was used to detect changes in rat skin surface temperature associated with experimental cancer development (Walker 256 carcinoma), inflammation (upon s.c. Sephadex injection) and haematoma (provoked by s.c. blood coagulate injection). Infrared camera with a geometric resolution of 76,800 pixels, spectral range of 8–14μm and the minimal detectable temperature resolution of 0.07°C with spatial resolution of 0.48mm at measuring distance of 30cm was used to obtain computerised thermal scans. Genuine ThermoWEB software developed for remote internet control as open source software was used. Results: The raise of peripheral temperature was observed after induction of local inflammation or haematoma. Opposite to that, transient decrease of the skin surface temperature was observed after tumour transplantation. Progressive growth of tumour was associated with the raise of the skin surface temperature from the 10th day after tumour inoculation, when the tumours developed supportive neoangiogenic blood supply, as verified by histology. Conclusion: While the raise of peripheral temperature in advanced tumour was caused by neoangiogenesis, the reduction in skin surface temperature in an early period after tumour cell inoculation indicated a decay of transplanted tumour cells due to the immune response and the lack of blood supply. Thus, infrared thermal imaging may have considerable value in evaluation of the tumour development and discrimination of cancer from inflammation and haematoma.

High expression of α 2, 3-linked sialic acid residues is associated with the metastatic potential of human gastric cancer

Abstract: Background: Sialic acid, as a terminal saccharide residue on cell surface glycoconjugates, plays an important role in a variety of biological processes. However, the precise nature of the molecules in gastric cancers has not been unveiled nor documented to be of clinical relevance. Herein, we measured the expression of α 2, 3-linked sialic acid residues by using a specific lectin as well as the potential of invasion and metastasis of gastric cancer was analyzed. Methods: The expression of α 2, 3-linked sialic acid residues in 100 cases of gastric cancer samples was evaluated using Maackia amurensis leukoagglutinin (MAL) histochemical staining analysis. The assays of cytochemical staining and flow cytometry were employed to determine the MAL positive cells in the gastric cancer cell lines. The activities of invasion and migration were evaluated using the assays of cell adhesion and transwell chamber. Results: The staining of MAL in gastric cancer tissues showed that high levels of α 2, 3-linked sialic acid residues were closely associated with the invasive depth (P=0.0003) and lymph node metastasis (P=0.0441). In gastric adenocarcinoma cell lines, SGC-7901, the highly metastatic cell line, displayed the most positive reaction with MAL among the selected cell lines. The potential of invasion and migration was confirmed using the assays of adhesion and transwell chamber that SGC-7901 exhibited the high activity of adhesion to extracellular matrix (ECM) and penetration to Matrigel. Conclusion: These results suggested that high level of α 2, 3-linked sialic acid residues was associated with metastatic potential of gastric cancer cells.

Development of a rat model by 3,4-benzopyrene intra-pulmonary injection and evaluation of the effect of green tea drinking on p53 and bcl-2 expression in lung carcinoma

Qihua Gu, Chengping Hu, Qiong Chen, Ying Xia, Juntao Feng, Hongzhong Yang

Abstract: Background A convenient animal model of primary lung cancer is compelling for investigation into the disease mechanisms and for development of therapeutic strategies. This study aims to develop a reproducible rat model for lung carcinoma by intra-pulmonary injection of 3,4-benzopyrene, and to evaluate the preventive effect of green tea on the formation of lung carcinoma. Methods Sprague–Dawley rats of the same ages were randomly assigned into three groups treated differently. Rats in group one were given green tea in drinking water (tea concentration: 1.2%; tea polyphenols in the tea solution: 0.3%); rats in the groups two and three were given blank drinking water. Rats in the groups one and two were injected intra-pulmonarily with 3,4-benzopyrene dissolved in corn oil (2mg/0.2mL/injection, fortnightly, 4 times in all); rats in the group three were injected with the vehicle corn oil as the control for injection. All the rats were sacrificed one year after the first intra-pulmonary injection. Tumors developed in rats and lung tissues were collected for carcinoma diagnosis and for p53 and bcl-2 expression. Results Intra-pulmonary injection of 3,4-benzopyrene steady induced lung carcinoma at a success rate of 75%. Administration with green tea drinking significantly reduced the incidence of lung carcinoma to 30%. Green tea up-regulated p53 expression in lung carcinoma, but significantly down-regulated bcl-2 expression. Conclusions Intra-pulmonary injection of 3,4-benzopyrene can steady induce lung carcinoma in rats, and green tea has preventive effect against lung cancer possibly by regulating expression of some critical genes such as p53 and bcl-2.

Chemopreventive action of dexamethasone and α-tocopherol in oxidative stressed cells

P. Baumeister, G. Korn, A. Berghaus, C. Matthias, U. Harréus

Abstract: Introduction: Recent research indicates a close connection of inflammation and cancer as presumed by Virchow in 1893. The growing understanding of cellular signalling and regulatory pathways reveals multiple links between inflammation and cancer. This study was designed to evaluate the influence of the anti-inflammatory drug dexamethasone and the antioxidant α-tocopherol on oxidative induced DNA damage, a major factor in the development of malignancies. Material and methods: Miniorgan cultures (MOC) of fresh biopsied human nasal mucosa were used to keep cells in their microenvironment and thus to mimic in vivo conditions. MOC were pretreated with dexamethasone and α-tocopherol in different concentrations on 1 or on 5 days before oxidative DNA damage was introduced by hydrogen peroxide. The effect of these substances on DNA damage was evaluated using the alkaline single cell microgel electrophoresis (Comet Assay). Results: Dexamethasone induced slight, but considerable DNA fragmentation by itself. It effectively protected cells from hydrogen peroxide induced DNA damage, leading to a maximum decrease of about 45% when preincubated on 5 days at 20μM. α-Tocopherol most effectively reduced oxidative DNA fragmentation by about 38% when MOC were pretreated 5 days at 20μM. Discussion: Our experimental data clearly shows the DNA protective action of dexamethasone and α-tocopherol with regard to oxidatively induced DNA damage, a major pathogenetic factor that inflammation and cancer have in common.

Melanoma metastasis to the breast: A diagnostic pitfall

Gulistan Bahat, Yasar Colak, Bulent Saka, Mehmet Akif Karan, Nesimi Buyukbabani

Abstract: Background: Breast metastasis is an extremely rare phenomenon. While nearly every malignancy has been described to metastasize to the breast; melanoma, lymphoma and leukemia tend to be the most common. Among these primary tumors, melanoma metastasis represents a diagnostic pitfall for both the clinicians and histopathologists. Methods: We report a case of widely metastatic malignant melanoma with diagnostic difficulties in both clinical and histopathological evaluation. Thorax CT, Abdominal MRI, tumor marker screening and two biopsies were performed to conclude the primary. Results: In clinical evaluation, there were rapidly proliferating multiple nodular lesions at the skin, breasts, lungs, ovaries and peritoneum accompanied by only increased CA 125 in tumor marker panel. The initial biopsy performed from a skin nodule was concordant with a metastatic carcinoma suggesting breast as the primary. The diagnosis was made by immunohistochemical staining of the second biopsy performed from a breast nodule. Conclusion: Although no strict clinical criteria exist to differentiate a melanoma metastasis to the breast from a primary breast carcinoma atypically rapid growth, normal Ca 15-3 level, and a history of prior melanoma may be helpful. However, it may be still misdiagnosed in some cases even histopathologically if the immunohistochemical staining is not performed.