Location of metastases in cancer of unknown primary are not random and signal familial clustering

Cancer of unknown primary and the «seed and soil» hypothesis

The worldwide incidence rate of cancer of unknown primary (CUP) reaches 5% (Kang et al, 2021; Lee, Sanoff, 2020; Yang et al, 2022). CUP has an alarmingly high mortality rate, with 84% of patients succumbing within the first year following diagnosis (Registration and Service, 2018). Under normal circumstances, tumor cell metastasis follows the «seed and soil» hypothesis, displaying a tissue-specific pattern of cancer cell homing behavior based on the microenvironment composition of secondary organs. In this study, we questioned whether seed and soil concept applies to CUP, and whether the pattern of tumor and metastasis manifestations for cancer of known primary (CKP) can be used to inform diagnostic strategies for CUP. We compared data from metastatic and primary CUP foci to the metastasis patterns observed in CKP. Furthermore, we evaluated several techniques for identifying the tissue-of-origin (TOO) in CUP profiling, including DNA, RNA, and epigenetic TOO techniques.

Metastatic Adenocarcinoma of Mandible with Unknown Primary Origin (CUP Syndrome): a Rare Case Report

Metastatic lesions of the jaws are a diagnostic challenge because of their scarcity and uncharacteristic clinical-radiographic features. Carcinoma of unknown primary origin (CUP) is characterized by the existence of metastatic disease with no recognized primary neoplasm after a comprehensive work-up. CUP shows a poor prognosis with limited treatment choices. This paper presents a 64-year-old male with a chief complaint of paresthesia of the chin and lower lip. Panoramic radiography showed an ill-defined radiolucency in the left mandibular molar area and the residue of the first molar root. Microscopic examination demonstrated features of mucin-producing adenocarcinoma and was not similar to common neoplasms of the jaw. The whole-body scan revealed multiple osseous uptakes. CDX2 was diffusely positive. However, in the end, the origin of the primary tumor was not determined. Considering the aforementioned data, the diagnosis of metastatic adenocarcinoma with unknown primary origin was made. CUP of the oral cavity is an extremely rare event. The possibility of metastasis should be raised in a patient who complains of paresthesia. Awareness of the clinical and histopathologic features of these malignancies is crucial for clinicians and pathologists to have a proper diagnosis.

Family history of cancer in first degree relatives and risk of cancer of unknown primary

Objective

Cancer of Unknown Primary (CUP) refers to the presence of metastatic lesions, with no identifiable primary site during the patient's lifetime. Poor survival and lack of available treatment highlight the need to identify potential CUP risk factors. We investigated whether a family history of cancer is associated with increased CUP risk.

Methods

We performed a case cohort analysis using data from the Netherlands Cohort Study, which included a total of 963 CUP cases and 4,288 subcohort members. A Cox Proportional Hazards Regression was used to compare CUP risk in participants who reported to have a family member with cancer to those who did not, whilst adjusting for confounders.

Results

In general, we observed no increased CUP risk in those who reported a family history of cancer. CUP risk appeared slightly increased in those who reported cancer in a sibling (HR: 1.16, 95% CI: 0.97–1.38), especially in those with a sister with cancer compared with those without (HR: 1.23, 95% CI: 0.99–1.53), although these findings are not statistically significant.

Conclusion

Having a family history of cancer is not an independent risk factor of CUP.

Brain Metastasis from Unknown Primary Tumour: Moving from Old Retrospective Studies to Clinical Trials on Targeted Agents

Simple Summary

Brain metastases (BMs) are the most common intracranial tumours in adults and occur up to 3–10 times more frequently than primary brain tumours. In up to 15% of patients with BM, the primary tumour cannot be identified. These cases are known as BM of cancer of unknown primary (CUP) (BM-CUP). The understanding of BM-CUP, despite its relative frequency and unfavourable outcome, is still incomplete and clear indications on management are missing. The aim of this review is to summarize current evidence on the diagnosis and treatment of BM-CUP.

Abstract

Brain metastases (BMs) are the most common intracranial tumours in adults and occur up to 3–10 times more frequently than primary brain tumours. BMs may be the cause of the neurological presenting symptoms in patients with otherwise previously undiagnosed cancer. In up to 15% of patients with BMs, the primary tumour cannot be identified. These cases are known as BM of cancer of unknown primary (CUP) (BM-CUP). CUP has an early and aggressive metastatic spread, poor response to chemotherapy, and poor prognosis. The pathogenesis of CUP seems to be characterized by a specific underlying pro-metastatic signature. The understanding of BM-CUP, despite its relative frequency and unfavourable outcome, is still incomplete and clear indications on management are missing. Advances in diagnostic tools, molecular characterization, and target therapy have shifted the paradigm in the approach to metastasis from CUP: while earlier studies stressed the importance of finding the primary tumour and deciding on treatment based on the primary diagnosis, most recent studies focus on the importance of identifying targetable molecular markers in the metastasis itself. The aim of this review is to summarize current evidence on BM-CUP, from the diagnosis and pathogenesis to the treatment, with a focus on available studies and ongoing clinical trials.

Progress in refining the clinical management of cancer of unknown primary in the molecular era

Cancer of unknown primary (CUP) is an enigmatic disease entity encompassing heterogeneous malignancies without a detectable primary tumour, despite a thorough diagnostic workup. A minority of patients with CUP (15-20%) can be assigned a putative primary tissue of origin according to clinical and histopathological findings and typically have a more favourable prognosis with the use of corresponding tumour type-specific therapies. Thus, the majority of patients with CUP have disease that cannot be assigned to a culprit primary tumour, are treated with empirical chemotherapy and have a poor prognosis. In the molecular era, the use of (epi)genomic or transcriptomic CUP classifiers and DNA or RNA sequencing offers two, sometimes overlapping, therapeutic strategies: tumour type-specific therapy and biomarker-guided therapy. Published data reveal that the accuracy of site-of-origin predictions made using CUP classifiers ranges between 54% and 98% when compared with the assignment made according to the recommended clinicopathological criteria. These advances have led to promising results in non-randomized prospective studies evaluating the efficacy of tumour type-specific therapy; however, the favourable outcomes were not confirmed in randomized controlled studies comparing this approach with standard empirical chemotherapy. Currently, the evidence supporting the use of biomarker-guided therapies is limited to case reports and small case series. In this Review, we discuss the clinical management of CUP in the era of precision medicine. We focus on the advances in understanding the biology of CUP, the implications for the diagnosis and classification of CUP according to the tissue of origin and the shift away from empirical therapy towards tailored therapy.

Exploring the biological hallmarks of cancer of unknown primary: where do we stand today?

Cancer of unknown primary (CUP) affects a small percentage of the general population. Nonetheless, a substantial number of these patients have a poor prognosis and consequently succumb to their illness within a year of diagnosis. The natural history of CUP is characterised by early metastasis from the unknown primary site, aggressive course and resistance to conventional chemotherapy. Unfortunately, the processes by which this orphan disease originates and progresses have not been fully elucidated and its biology remain unclear. Despite the conceptual progress in genetic and molecular profiling made over the past decade, recognition of the genetic and molecular abnormalities involved in CUP, as well as the identification of the tissue of origin remain unresolved issues. This review will outline the biology of CUP by exploring the hallmarks of cancer in order to rationalise the complexities of this enigmatic syndrome. This approach will help the reader to understand where research efforts currently stand and the pitfalls of this quest.

Advances in the management of brain metastases from cancer of unknown primary

Cancer of unknown primary accounts for 3-5% of all cancers for which an adequate investigation does not identify the primary tumor. The particular subset of brain metastasis in cancer of unknown primary (BMCUP) is a clinical challenge that lacks standardized diagnostic and therapeutic options. It is diagnosed predominantly in male patients in the sixth decade of age with complaints of headache, neurological dysfunction, cognitive and behavioral disturbances and seizures. The therapeutic approach to patients with BMCUP relies on local control and systemic treatment. Surgery or stereotactic radiosurgery and/or whole brain radiation therapy seems to be the cornerstone of the treatment approach to BMCUP. Systemic therapy remains essential as cancers of unknown primary are conceptually metastatic tumors. The benefits of chemotherapy were disappointing whereas those of targeted therapies and immune checkpoint inhibitors remain to be evaluated. In this Review, we address the advances in the diagnosis and treatment of BMCUP.

Familial cancer of unknown primary

Cancer of unknown primary site (CUP) is a deadly disease diagnosed through metastases at various organs without primary tumor identification. Despite the major molecular and technological advances, the carcinogenesis of CUP remains enigmatic which hampers adequate study design of treatments leading to survival improvement. To date, the pathogenesis of CUP is still debatable with one hypothesis considering CUP simply a group of metastatic tumors with unidentified primaries and another considering it a distinct entity with specific genetic and phenotypic aberrations. Familial CUP seems to favor the first hypothesis due to common genetic predisposition factors between known primaries and CUP. Two clinical implications may be withdrawn from the pathogenesis of familial clustering of CUP. The detailed family history and environmental risk factors may orient towards the primary tumor identification. Smoking avoidance and adherence to general population guidelines for cancer screening would be strongly encouraged.

Familial Risks and Mortality in Second Primary Cancers in Melanoma

Background

Malignant melanoma (MM) patients are at increasing risk of developing second primary cancers (SPCs). We assessed mortality and risk of SPCs in MM patients with siblings or parents affected with same cancer compared with that of the general population.

Methods

We used the Swedish Family-Cancer Database to assess relative risks (RRs) and causes of death in SPCs until 2015 in patients with a MM diagnosis between 1958 and 2015. We identified 35 451patients with MM among whom 3212 received a subsequent diagnosis of SPC. RRs of SPCs after MM diagnosis were calculated stratifying over concordant family history of cancer in first-degree relatives.

Results

Familial RRs were increased for second melanoma (RR = 19.28, 95% CI = 16.71 to 22.25), squamous cell skin cancer (RR = 7.58, 95% CI = 5.57 to 10.29), leukemia (RR = 5.69, 95% CI = 2.96 to 10.94), bladder (RR = 4.15, 95% CI = 2.50 to 6.89), ovarian (RR = 3.89, 95% CI = 1.46 to 10.37), kidney cancer (RR = 3.77, 95% CI = 1.57 to 9.06), cancer of unknown primary (RR = 3.67, 95% CI = 1.65 to 8.16), nervous system (RR = 2.88, 95% CI = 1.20 to 6.93), breast (RR = 2.34, 95% CI = 1.92 to 2.84), lung (RR = 2.24, 95% CI = 1.50 to 3.35), and prostate cancer (RR = 2.22, 95% CI = 1.89 to 2.61) with statistical significance. For all cancers, familial RR was in excess (2.09, 95% CI = 2.02 to 2.16 vs 1.78, 95% CI = 1.69 to 1.87; P_trend < .0001). Cause of death in MM patients with SPC is shown to be dependent on the cancer site though SPCs contributed to majority of deaths.

Conclusions

SPCs appear higher with prior family history of cancer and contribute to mortality. SPC was the most common cause of death in patients with SPC and is almost uniformly the major contributing cause of death for all cancer sites. For improved survival in MM patients, prevention and early detection of SPCs would be important.

Diagnosis and management of metastatic neoplasms with unknown primary

In cancer of unknown primary (CUP), metastases are clinically and histologically confirmed, but the primary tumor site remains elusive after extensive work-up. CUPs make up for 2-3% of all epithelial malignancies. The two prevailing histologies are adenocarcinomas and undifferentiated carcinomas, whereas squamous cell carcinomas, neuroendocrine carcinomas and rare histologies account for the remaining 10%. The diagnostic work-up in CUP relies strongly on a detailed immunohistological (IHC) analysis in order to characterize the tumor type, nowadays aided by molecular techniques. Diagnostics also include a thorough clinical examination, a basic lab draw with the most relevant tumor markers, and cross sectional imaging. Additional PET-CT is recommended in cervical lymph nodes suggestive of head and neck cancer and in limited metastases potentially treatable in curative intent. As for treatment, it is paramount to identify patients who fall into one of the six well defined "favorable" subset categories, namely extragonadal germ cell tumors, adenocarcinoma with isolated unilateral axillary lymph nodes in female patients, squamous cell carcinoma with neck lymph nodes, squamous cell carcinoma with inguinal lymph nodes, serous papillary peritoneal carcinomatosis in females and blastic bone metastasis in males with elevated PSA. These subsets are distinct both regarding the required treatment and the comparably favorable prognosis. Within the remaining "unfavorable" group, patients of colon and renal cancer type should be identified based on IHC and clinical picture, since the prognosis of these patients seems to improve with the use of therapy tailored to the presumed primary as well. For the few patients with limited metastases it should be assessed whether they are candidates for surgery, radiotherapy or surgery followed by irradiation in curative intent. The remaining majority of patients are treated with empiric palliative chemotherapy, typically a platinum - paclitaxel combination, though the level of evidence for this therapy recommendation is low. Gemcitabine alone or in combination can be used as an alternative. Decoding of the molecular profiles in CUP offers the prospect of targeted therapy with novel agents. However, there appears to be no uniform molecular pattern for CUP, and the observed molecular diversity thus poses a challenge to respective clinical trials.

Familial associations of female breast cancer with other cancers

Familial risks of breast cancer (BC) are well established but whether BC clusters with other, i.e. discordant, cancers is less certain but of interest for the identification of common genetic and possible environmental factors contributing to a general cancer susceptibility. We apply a novel approach to search for familial associations of BC with other (discordant) cancers based on the Swedish Family-Cancer Database. Relative risks (RRs) were calculated for BC in families with increasing numbers of patients with discordant cancer X, and conversely, familial RRs for cancer X in families with increasing numbers of BC patients. Joint p-values were calculated from independent analyses. The total number of familial BCs was 12,266, 14.9% with one first-degree relative with BC and 1.2% with at least 2 affected relatives. Ovarian and prostate cancers showed the strongest associations with BC (p-value <10^-11 ). The p-value for melanoma was <10^-6 , for stomach and male colorectal cancer <2.5 × 10^-6 , for cancer of unknown primary <2.5 × 10^-5 and for lung cancer <5 × 10^-5 . Significance level <5 × 10^-4 was reached with pancreatic cancer. The remaining associations (p < 0.0025) included thyroid, endometrial, testicular, eye cancers (uveal melanoma), nervous system and endocrine tumors and non-Hodgkin lymphoma. The RR for BC increased by increasing numbers of patients with any cancer in family members and it reached 1.62 when three or more family members were affected. The results suggest that BC shares susceptibility with a number of other cancers. This might alert genetic counselors and challenge approaches for gene and gene-environment identification.

Other cancers in lung cancer families are overwhelmingly smoking-related cancers

Familial risks of lung cancer are well-established, but whether lung cancer clusters with other discordant cancers is less certain, particularly beyond smoking-related sites, which may provide evidence on genetic contributions to lung cancer aetiology.

We used a novel approach to search for familial associations in the Swedish Family-Cancer Database. This involved assessment of familial relative risk for cancer X in families with increasing numbers of lung cancer patients and, conversely, relative risks for lung cancer in families with increasing numbers of patients with cancers X. However, we lacked information on smoking.

The total number of lung cancers in the database was 125 563. We applied stringent statistical criteria and found that seven discordant cancers were associated with lung cancer among family members, and six of these were known to be connected with smoking: oesophageal, upper aerodigestive tract, liver, cervical, kidney and urinary bladder cancers. A further novel finding was that cancer of unknown primary also associated with lung cancer. We also factored in histological evidence and found that anal and connective tissue cancers could be associated with lung cancer for reasons other than smoking. For endometrial and prostate cancers, suggestive negative associations with lung cancer were found.

Although we lacked information on smoking it is prudent to conclude that practically all observed discordant associations of lung cancer were with cancers for which smoking is a risk factor.

Among family members of lung cancer patients, 7 other cancers were found, all of which were smoking relatedhttp://ow.ly/ZLnt30csVfZ

Risk of other Cancers in Families with Melanoma: Novel Familial Links

A family history of cutaneous melanoma (‘melanoma’) is a well-established risk factor for melanoma. However, less is known about the possible familial associations of melanoma with other discordant cancers. A risk for discordant cancer may provide useful information about shared genetic and environmental risk factors and it may be relevant background data in clinical genetic counseling. Using the Swedish Family-Cancer Database, we assessed the relative risk (RR) for any cancer in families with increasing numbers of first-degree relatives diagnosed with melanoma, including multiple melanoma, and in reverse order RR for melanoma in families of multiple discordant cancers. Close to 9% of melanoma was familial; among these 92% were in 2-case families and 8% in families with 3 cases or more. Cancers that were associated with melanoma, in at least two independent analyses, included breast, prostate, colorectal, skin and nervous system cancers. Other associations included cancer of unknown primary, acute myeloid leukemia/myelofibrosis and Waldenström macroglobulinemia/myeloma. Significant results, which appear biologically plausible, were also obtained for rare nasal melanoma and mesothelioma. Although small samples sizes and multiple comparisons were of concern, many of the above associations were internally consistent and provide new diverse leads for discordant familial association of melanoma.

Experimental study on the inhibition effect of miR-106a inhibitor on tumor growth of ovarian cancer xenografts mice

OBJECTIVE

To study the inhibition effect of miR-106a inhibitor on tumor growth of ovarian cancer xenografts mice.

METHODS

BALB/c mice were selected as experimental animals, ovarian cancer SKOV-3 cells transfected with miR-106a inhibitor and its negative control were inoculated subcutaneously, intratumoral injection of miR-106a inhibitor and its negative control were continued after tumor formation, and they were enrolled as treatment group and model group, respectively. Tumor volume and weight as well as Ki-67 and programmed cell death 4 (PDCD4) expression were determined; miR-106a inhibitor and its negative control as well as miR-106a mimic and its negative control were transfected into SKOV-3 cells, and expression of PDCD4 in cells was determined.

RESULTS

Tumor tissue volume and weight as well as mRNA expression and protein expression of Ki-67 in treatment group were significantly lower than those in the model group while mRNA expression and protein expression of PDCD4 were significantly higher than those in the model group; transfection of miR-106a mimic could decrease mRNA expression and protein expression of PDCD4 in SKOV-3 cells, and transfection of miR-106a inhibitor could increase mRNA expression and protein expression of PDCD4 in SKOV-3 cells.

CONCLUSIONS

Transfection of miR-106a inhibitor can inhibit the growth of tumor in ovarian cancer xenografts mice through increasing the expression of PDCD4.