Squamous cell cancer of the cervix, immune senescence and HPV: is cervical cancer an age-related neoplasm?

Differentially Expressed Genes and Molecular Susceptibility to Human Age-Related Diseases

Mainstream transcriptome profiling of susceptibility versus resistance to age-related diseases (ARDs) is focused on differentially expressed genes (DEGs) specific to gender, age, and pathogeneses. This approach fits in well with predictive, preventive, personalized, participatory medicine and helps understand how, why, when, and what ARDs one can develop depending on their genetic background. Within this mainstream paradigm, we wanted to find out whether the known ARD-linked DEGs available in PubMed can reveal a molecular marker that will serve the purpose in anyone's any tissue at any time. We sequenced the periaqueductal gray (PAG) transcriptome of tame versus aggressive rats, identified rat-behavior-related DEGs, and compared them with their known homologous animal ARD-linked DEGs. This analysis yielded statistically significant correlations between behavior-related and ARD-susceptibility-related fold changes (log₂ values) in the expression of these DEG homologs. We found principal components, PC1 and PC2, corresponding to the half-sum and the half-difference of these log₂ values, respectively. With the DEGs linked to ARD susceptibility and ARD resistance in humans used as controls, we verified these principal components. This yielded only one statistically significant common molecular marker for ARDs: an excess of Fcγ receptor IIb suppressing immune cell hyperactivation.

Bimodal Age Distribution in Cancer Incidence

Cancer is caused by accumulation of genetic changes which include activation of protooncogenes and loss of tumor suppressor genes. The age-specific incidence of cancer in general increases with advancing age. However, some cancers exhibit a bimodal distribution. Commonly recognized cancers with bimodal age distribution include acute lymphoblastic leukemia, osteosarcoma, Hodgkin's lymphoma, germ cell tumors and breast cancer. Delayed infection hypothesis has been used to provide explanation for the early childhood peak in leukemias and lymphomas, whereas the peak at an older age is associated with accumulation of protooncogenes and weakened immune system. Further genetic analysis and histopathological variations point to distinctly different cancers, varying genetically and histologically, which are often combined under a single category of cancers. Tumor characteristics and age distribution of these cancers varies also by population groups and has further implications on cancer screening methods. Although significant advances have been made to explain the bimodal nature of such cancers, the specific genetic mechanisms for each age distribution remain to be elucidated. Further distinction among the different cancer subtypes may lead to improvements in individual risk assessments, prevention and enhancement of treatment strategies.

Prevalence and Distribution of Human Papillomavirus Genotypes Among Women in Kinshasa, The Democratic Republic of the Congo

PURPOSE

Cervical cancer is the leading cause of mortality by cancer in sub-Saharan Africa. The human papillomavirus (HPV) infection is recognized as a necessary and sufficient cause for cervical cancer. Population-specific estimates of HPV prevalence in the Democratic Republic of the Congo (DRC) are unknown. This study aims to estimate the prevalence of HPV and identify predominant genotypes circulating in Kinshasa, DRC.

METHODS

Between July 2015 and July 2017, women were invited to attend a screening program at Mont-Amba Health Centre in Kinshasa. Cervical specimens were collected using the Preservcyt medium. HPV DNA testing was performed for all specimens using real-time polymerase chain reaction.

RESULTS

During the 2-year period, a total of 1,870 women age 25 to 82 years were screened. The mean age was 46 years (± 11.4 years). The overall HPV prevalence was 28.2% (95% CI, 26.1% to 30.3%). High-risk HPV prevalence was 24.8% (95% CI, 22.8% to 26.8%). Women younger than 30 years had the highest overall HPV prevalence (42.2%; 95% CI, 34.7% to 49.9%). A second peak of prevalence was observed in women age 60 years and older. HPV68 (5.5%; 95% CI, 4.5% to 6.6%) was the most prevalent HPV type.

CONCLUSION

The distribution of HPV genotypes among women in our population was different compared with other world regions. A key finding was that HPV68 was the most prevalent high-risk HPV genotype. These findings highlight the need for the determination in our population of the etiologic fraction of different HPV types in invasive cervical cancers.

Human Papillomavirus Prevalence Among American Indian Women of the Great Plains

BACKGROUND

High-risk human papillomavirus (hrHPV) causes cervical cancer. In the United States, approximately 40% of women aged 14-59 years from all racial and ethnic groups are infected with HPV, and prevalence typically declines with age. However, American Indian (AI) women are insufficiently sampled to permit a population-specific estimate of hrHPV prevalence.

METHODS

Vaginal swabs were self-collected by 698 AI women aged 21-65 years from a tribal community in the Great Plains. We estimated the population prevalence of hrHPV and identified predominant genotypes.

RESULTS

The combined prevalence of hrHPV genotypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68 was 34.8%. HPV-51 (7.6%), HPV-58 (5.3%), HPV-52 (4.3%), HPV-18 (4.3%), and HPV-16 (3.9%) were most prevalent. hrHPV prevalence declined with age, from 42.2% in women aged 21-24 years to 27.9% in women aged 50-65 years.

CONCLUSIONS

HPV-51 was the single most prevalent oncogenic genotype. The combined prevalence of hrHPV among AI women in our sample was high, particularly among women aged 50-65 years, for whom hrHPV prevalence was approximately triple that of other races. Cervical cancer screening efforts should be increased, particularly among women from the community aged 30 years and older.

Epidermal growth factor facilitates epinephrine inhibition of P2X7-receptor-mediated pore formation and apoptosis: a novel signaling network

Epidermal growth factor (EGF), epinephrine, and the P2X7 receptor system regulate growth of human uterine cervical epithelial cells, but little is known about how these systems intercommunicate in exerting their actions. The objective of this study was to understand the mechanisms of EGF and epinephrine regulation of growth of cervical cells. Treatment of cultured CaSki cells with 0.2 nM EGF increased cell number via a PD98059-sensitive pathway. Treatment with 2 nM epinephrine increased cell number, and the effect was facilitated by cotreatment with EGF. Whereas the effect of EGF alone involved up-regulation of [3H]-thymidine incorporation and an increase in cell proliferation, the effect of epinephrine was mediated by inhibition of apoptosis. Epinephrine inhibited apoptosis induced by the P2X7 receptor ligand 2',3'-0-(4-benzoylbenzoyl)-ATP, by attenuation of P2X7 receptor plasma membrane pore formation. Cotreatment with EGF facilitated epinephrine effect via a phosphoinositide 3-kinase-dependent mechanism. CaSki cells express the beta2-adrenoceptor, and the epinephrine antiapoptotic effect could be mimicked by beta2-adrenoceptor agonists and by activators of adenylyl cyclase. Likewise, the effect could be blocked by beta2-adrenoceptor blockers and by the inhibitor of protein kinase-A H-89. Western immunoblot analysis revealed that epinephrine decreased the levels of the glycosylated 85-kDa form of the P2X7 receptor and increased receptor degradation, and that EGF potentiated these effects of epinephrine. EGF did not affect cellular levels of the beta2-adrenoceptor. In contrast, EGF, acting via the EGF receptor, augmented beta2-adrenoceptor recycling, and it inhibited beta2-adrenoceptor internalization via a phosphoinositide 3-kinase-dependent mechanism. We conclude that, in cervical epithelial cells, EGF has a dual role: as mitogen, acting via the MAPK/MAPK kinase pathway, and as an antiapoptotic factor by facilitating epinephrine effect and resulting in greater expression of beta2-adrenoceptors in the plasma membrane. These findings underscore a novel signaling network of communication between the receptor tyrosine kinases, the G protein-coupled receptors, and the purinergic P2X7 receptor.

P2X7 receptor-mediated apoptosis of human cervical epithelial cells

Normal human ectocervical epithelial (hECE) cells undergo apoptosis in culture. Baseline apoptosis could be increased by shifting cells to serum-free medium and blocked by lowering extracellular calcium. Treatment with the ATPase apyrase attenuated baseline apoptosis, suggesting that extracellular ATP and purinergic mechanisms control the apoptosis. Treatment with ATP and the P2X7 receptor analog 2'-3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate (BzATP) increased apoptosis significantly, in a time- and dose-related manner. The threshold of ATP effect was 0.5 microM in hECE cells and approximately 1 microM in CaSki cancer cells. The apoptotic effect of BzATP was additive in part to that of tumor necrosis factor (TNF)-alpha, and it could be attenuated by lowering extracellular calcium and by treatment with the caspase-9 inhibitor Leu-Glu-His-Asp-O-methyl-fluoromethylketone (LEHD-FMK). Treatment with BzATP activated caspase-9, and, in contrast to TNF-alpha, it had only a mild effect on caspase-8. Both BzATP and TNF-alpha activated caspase-3, suggesting that BzATP activates predominantly the mitochondrial apoptotic pathway. Both hECE and CaSki cells secrete ATP into the extracellular fluid, and mean ATP activity in conditioned medium was approximately 0.5 microM, which is in the range of values that suffice to activate the P2X7 receptor. On the basis of these findings we propose a novel autocrine-paracrine mechanism of cervical cell apoptosis that operates by P2X7 receptor control of cytosolic calcium and utilizes the mitochondrial apoptotic pathway.

Advancing age and cervical cancer screening and prognosis

OBJECTIVES

To determine associations between advancing age and screening behavior and prognosis in long-term members of a prepaid health plan diagnosed with invasive cervical cancer (ICC).

DESIGN

Case series.

SETTING

Prepaid health plan.

PARTICIPANTS

All women diagnosed with ICC at Kaiser Permanente Medical Care Program-Northern California health plan from 1988 to 1994.

MEASUREMENTS

From medical records, we recorded participants' age, stage at diagnosis, tumor histology, and results of and reasons for all previous cervical smears. We limited our analysis to women who had been members of the health plan for at least 30 of the 36 months preceding diagnosis (n = 455).

RESULTS

Women in older age groups were less likely than younger women to have been screened within the 3 years before diagnosis (P = .005 for trend). Nonadherence to follow-up of abnormal cervical smears was uncommon (17/455, 3.7%) and not age related (P = .932 for trend). The proportions of ICC that were interval cancers, defined as ICC diagnosed within 3 years of a negative screening smear, were highest in women under age 30 (P = .004 for trend). In multivariate analyses controlling for stage at diagnosis, women age 60 and older were not more likely to die of ICC within 3 years of diagnosis than were women younger than age 60 (odds ratio 1.30, 95% confidence interval 0.75-2.28).

CONCLUSION

The disproportionate burden of cervical cancer observed in older women appears to be largely attributable to lack of screening within the 3 years before diagnosis.

Management of cervical cancer in pregnancy

Carcinoma of the cervix is the most common gynecologic cancer found during pregnancy. Management and treatment of this condition depend on cancer stage, estimated gestational age, and ethical, religious, and personal desires. Review of the medical literature in English from 1965 to 1998 is presented with recommendations for management.

Cervical cancer in older women: a molecular analysis of human papillomavirus types, HLA types, and p53 mutations

OBJECTIVE

The purpose of this study was to evaluate cervical cancers in older women to determine whether they differed from tumors in younger women with respect to human papillomavirus types, frequencies of p53 mutations, and presence of a proposed high-risk HLA-DR2 haplotype.

STUDY DESIGN

Cervical tissue was obtained from women undergoing surgical treatment of in situ or invasive carcinoma of the cervix. Viral and genomic deoxyribonucleic acid was extracted. The presence of human papillomavirus deoxyribonucleic acid was detected by polymerase chain reaction amplification. Viral subtypes were assigned by means of a combination of type-specific amplification and automated sequencing of the L1 region. The presence of p53 mutations was evaluated by direct sequencing of exons 5 through 9. The HLA-DR locus was screened for the presence of the high-risk DRB1*1501 allele by means of selective polymerase chain reaction amplification followed by agarose gel electrophoresis of HLA-DR2 types.

RESULTS

Tumors from 39 women 62 to 85 years old were analyzed. Tumors from 104 younger women formed a reference group. Human papillomavirus 16 was found in 41% and 54% and human papillomavirus 18 was found in 10% and 12% of the tissue samples from older and younger women, respectively. The overall distributions of human papillomavirus types did not differ statistically between the groups. One of the 25 older patients tested had a p53 mutation. This tumor also had a positive test result for human papillomavirus 18. The DR*1501 allele was present in 33% of the older patients and 28% of the younger patients. The expected frequency of this allele in white Americans is 19.8%. The increased frequency of this allele among both older and younger women with cervical cancer was statistically significant (P < .05).

CONCLUSIONS

We hypothesized that cervical cancer in older women might differ from that in younger women with respect to human papillomavirus types, natural host immunity, or the frequency of nonviral origins of the cancer. The findings show, however, that tumors from older women are extremely similar to those from younger women with respect to the human papillomavirus types present and the infrequent occurrence of p53 mutations. In addition we found that an HLA-DR allele that is associated with a risk of cervical cancer in younger women is also associated with risk in older women. These findings are most consistent with a model similar to that in younger women but with an unusually long latency for the transforming effect of the virus in some hosts.

Human T-cell lymphotropic virus type I and severe neoplasia of the cervix in Jamaica

Human T-cell lymphotropic virus type I (HTLV-I) was associated with carcinoma of the cervix in Japan in a recent study that compared hospital cases with healthy population-based controls. To test this relationship in women more alike for cervical neoplasia risk factors (including sexual behavior and human papilloma virus; HPV), we enrolled consecutive patients from a colposcopy clinic in Kingston, Jamaica (an HTLV-I endemic area). Patients underwent Pap smear, colposcopy, biopsy and cervical swab for detection of HPV by polymerase chain reaction. Cases were defined as women with CIN-3 or invasive cancer (CIN-3/CA). Controls included all patients with either CIN-I or koilocytotic atypia, atypical squamous cells of undetermined significance or benign cervical pathology (all but one had at least inflammatory changes). Patients with CIN-2 were excluded to minimize risk of case-control misclassification. Cases were much more likely to be HTLV-I seropositive than controls. Although mean age differed significantly between cases (mean age = 39 years) and controls (mean age = 33 years), control for age did not explain the relation of CIN-3/CA with HTLV-I. Among HPV DNA positive subjects the age-adjusted association was not diminished but lost statistical significance. HTLV-I seroprevalence may be independently associated with progression to severe neoplasia of the cervix.