Cancer of Unknown Primary Site: Real Entity or Misdiagnosed Disease?

Use of novel genomic sequencing to characterise carcinoma of unknown primary (CUP) in patient with axillary lymphadenopathy

Carcinoma of unknown primary (CUP) comprises 2-5% of cancer diagnoses worldwide, with a prevalence that has modestly declined with increased availability of advanced diagnostic tools such as next-generation sequencing (NGS). This case presentation illustrates the possibilities and gaps that remain with improving diagnostic capabilities in identifying and effectively treating CUP. This is the case of a rapidly enlarging right axillary mass without a primary tumour site and histological evaluation demonstrating a poorly differentiated neoplasm. Tumour of origin testing using a clinically validated RNA-sequencing-based machine learning classifier unexpectedly suggested greatest probability of metastatic melanoma with lesser likelihood of fibrosarcoma. Subsequent clinical behaviour and lack of response to chemoimmunotherapy conflicted with NGS results, with a multidisciplinary team ultimately agreeing on final diagnosis of aggressive soft tissue sarcoma, specifically malignant peripheral nerve sheath tumour. The patient had a complete clinical response after forequarter amputation and a sarcoma-based chemotherapy regimen. This case highlights both the potential and current shortcomings of NGS and predictive tumour of origin analytic tools in helping with characterisation and categorisation of CUP. There is a need for improvement and optimisation of these diagnostic modalities, but they offer another option to improve historically poor outcomes in CUP.

Head and neck cancer of unknown primary: unveiling primary tumor sites through machine learning on DNA methylation profiles

BACKGROUND

The unknown tissue of origin in head and neck cancer of unknown primary (hnCUP) leads to invasive diagnostic procedures and unspecific and potentially inefficient treatment options for patients. The most common histologic subtype, squamous cell carcinoma, can stem from various tumor primary sites, including the oral cavity, oropharynx, larynx, head and neck skin, lungs, and esophagus. DNA methylation profiles are highly tissue-specific and have been successfully used to classify tissue origin. We therefore developed a support vector machine (SVM) classifier trained with publicly available DNA methylation profiles of commonly cervically metastasizing squamous cell carcinomas (n = 1103) in order to identify the primary tissue of origin of our own cohort of squamous cell hnCUP patient's samples (n = 28). Methylation analysis was performed with Infinium MethylationEPIC v1.0 BeadChip by Illumina.

RESULTS

The SVM algorithm achieved the highest overall accuracy of tested classifiers, with 87%. Squamous cell hnCUP samples on DNA methylation level resembled squamous cell carcinomas commonly metastasizing into cervical lymph nodes. The most frequently predicted cancer localization was the oral cavity in 11 cases (39%), followed by the oropharynx and larynx (both 7, 25%), skin (2, 7%), and esophagus (1, 4%). These frequencies concord with the expected distribution of lymph node metastases in epidemiological studies.

CONCLUSIONS

On DNA methylation level, hnCUP is comparable to primary tumor tissue cancer types that commonly metastasize to cervical lymph nodes. Our SVM-based classifier can accurately predict these cancers' tissues of origin and could significantly reduce the invasiveness of hnCUP diagnostics and enable a more precise therapy after clinical validation.

Advances in Cancer Research: Current and Future Diagnostic and Therapeutic Strategies

Cancers of unknown primary (CUP) exhibit significant cellular heterogeneity and malignancy, which poses significant challenges for diagnosis and treatment. Recent years have seen deeper insights into the imaging, pathology, and genetic characteristics of CUP, driven by interdisciplinary collaboration and the evolution of diagnostic and therapeutic strategies. However, due to their insidious onset, lack of evidence-based medicine, and limited clinical understanding, diagnosing and treating CUP remain a significant challenge. To inspire more creative and fantastic research, herein, we report and highlight recent advances in the diagnosis and therapeutic strategies of CUP. Specifically, we discuss advanced diagnostic technologies, including 12-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) or 68Ga-FAPI (fibroblast activation protein inhibitor) PET/CT, liquid biopsy, molecular diagnostics, self-assembling nanotechnology, and artificial intelligence (AI). In particular, the discussion will extend to the effective treatment techniques currently available, such as targeted therapies, immunotherapies, and bio-nanotechnology-based therapeutics. Finally, a novel perspective on the challenges and directions for future CUP diagnostic and therapeutic strategies is discussed.

Deciphering the origin and therapeutic targets of cancer of unknown primary: a case report that illustrates the power of integrative whole-exome and transcriptome sequencing analysis

Cancer of unknown primary (CUP) represents a significant diagnostic and therapeutic challenge, being the third to fourth leading cause of cancer death, despite advances in diagnostic tools. This article presents a successful approach using a novel genomic analysis in the evaluation and treatment of a CUP patient, leveraging whole-exome sequencing (WES) and RNA sequencing (RNA-seq). The patient, with a history of multiple primary tumors including urothelial cancer, exhibited a history of rapid progression on empirical chemotherapy. The application of our approach identified a molecular target, characterized the tumor expression profile and the tumor microenvironment, and analyzed the origin of the tumor, leading to a tailored treatment. This resulted in a substantial radiological response across all metastatic sites and the predicted primary site of the tumor. We argue that a comprehensive genomic and molecular profiling approach, like the BostonGene© Tumor Portrait, can provide a more definitive, personalized treatment strategy, overcoming the limitations of current predictive assays. This approach offers a potential solution to an unmet clinical need for a standardized approach in identifying the tumor origin for the effective management of CUP.

A rare and challenging case of extrahepatic costal metastases from an unknown primary hepatocellular carcinoma

Hepatocellular carcinoma (HCC) typically presents with a primary hepatic mass. Nevertheless, on rare occasions, the initial presentation can be exclusively related to extrahepatic metastases and the most common sites of metastases are the lungs, lymph nodes, bones, and adrenal glands. While, bone metastases are generally accompanied by multiple metastatic spreads elsewhere in the body or previously diagnosed HCC, cases of solitary bone metastases with no liver lesion at imaging have been reported. Indeed, two rare entities of HCC have been reported in the literature which are the ectopic hepatocellular carcinoma and the infiltrative type of hepatocellular carcinoma with a very challenging radiologic diagnosis and poor prognosis. In this article, we present a case of extrahepatic costal metastases of hepatocellular carcinoma, which was diagnosed through a bone biopsy, with no focal lesion on liver imaging including ultrasound, multiphase MRI, and CT scan except for the presence of a portal vein thrombosis. It is important to consider the possibility of HCC metastases when evaluating rapidly growing extrahepatic lesions in patients with chronic liver disease and to consider the tumor characteristics and imaging findings as well as limitations to make accurate and timely diagnosis leading to improved patient management. Our patient had probably an infiltrating HCC because of two prominent factors: the presence of portal vein thrombosis and a markedly elevated alpha-fetoprotein (AFP). A liver biopsy was crucial in order to confirm the diagnosis but unfortunately it could not be performed because of the unexpected death of the patient due to hemorrhagic shock. It is also worth noting in this case, that the elevated level of AFP raised the suspicion on an underlying HCC and contributed to more elaborate diagnostic tests.

CDX2- and PAX8-Expressing Subtypes in Female Urethral Adenocarcinoma: Pathogenesis Insights through Immunohistochemical and Morphological Analyses

Female urethral adenocarcinoma has attracted attention as a rare tumor type based on its differential pathogenesis from its male counterpart. However, to date, our knowledge concerning its immunohistochemical and morphological characteristics remains limited due to the small number of cases studied. In this study, nine consecutive cases of female urethral adenocarcinoma were used for immunohistochemical and morphological characterization of the tumor based on semi-comprehensive immunohistochemical analysis and detailed morphological evaluations. Our immunohistochemical assay revealed two subtypes of female urethral adenocarcinoma with distinctive staining patterns: the CDX2- and PAX8-expressing subtypes. The former stained positive for other intestinal markers (e.g., HNF4α and TFF1) as well (7 of 7 cases); the latter stained negative for these intestinal markers (0 of 2 cases) but stained positive for clear cell carcinoma markers (e.g., Napsin A and HNF1β) (2 of 2 cases). Regarding cytokeratins, the former displayed a CK7- and CK20-positive immunoprofile (7 of 7 cases); the latter exhibited a CK7-positive and CK20-negative immunoprofile (2 of 2 cases). Morphologically, CDX2- and PAX8-expressing subtypes resembled intestinal-type adenocarcinoma and clear cell carcinoma (occurring in gynecological organs), respectively. The semi-comprehensive immunoprofiling data presented in this study can potentially contribute to the correct diagnosis of this rare tumor type. Finally, our study represents an important basis for future investigations aiming to further elucidate the details and origin of female urethral adenocarcinoma, and it can potentially contribute to developing diagnostic and therapeutic strategies for treating this malignancy.

Bone metastatic carcinoma coexisting with plasma cell myeloma: a case report

OBJECTIVE

Multiple myeloma is a clonal plasma cell proliferation often causing bone lytic lesions. It is sometimes challenging to differentiate these lytic lesions associated with multiple myeloma from bone destruction due to a metastasis. Although coexistence of solid tumors and plasma cell myeloma in one patient has been described, synchronous skeletal metastases from both neoplasms occurring in the same bone lesion is exceptional. Indeed, only one case has been reported in the literature.

CASE PRESENTATION

Herein, we report a case involving a 68-year-old Caucasian male patient admitted to our department for coronavirus disease 2019 infection with incidental finding of multiple lytic bone lesions during hospitalization. Laboratory tests revealed an increased immunoglobulin G kappa M protein and high levels of carbohydrate antigen 19-9. Bone marrow aspiration showed increased atypical plasma cells consistent with multiple myeloma. Percutaneous image-guided biopsy of one of the osteolytic lesions was performed. Pathological examination identified both plasma cell neoplasm and poorly differentiated metastatic carcinoma within the same bone lytic lesions.

CONCLUSION

The present case raises awareness among clinicians and pathologists that clinical and radiologic suspicion of multiple myeloma may be within the spectrum of second primary malignancies.

Nationwide survey on family caregiver-perceived experiences of patients with cancer of unknown primary site

PURPOSE

Cancer of unknown primary site (CUP) is an aggressive disease with poor prognosis. As research on the experiences of CUP patients and their families is scarce, this study aimed to compare the family caregiver-perceived burden of CUP with that of common cancers (lung, colon, and stomach cancers). The association between family caregiver-perceived burden and CUP patients' quality of life (QOL) at end-of-life and family depression, respectively, was also explored.

METHODS

This was a pre-planned secondary analysis of nationwide cross-sectional survey data from the bereaved family caregivers of patients with cancer who died at 286 institutions. The major measurements were the eight-item family caregiver-perceived Burden scale (comprising specialist access, uncertainty, and prolonged diagnosis), Good Death Inventory, and Patient Health Questionnaire 9.

RESULTS

Of 27,591 survey responses, we analyzed 97 and 717 responses from family caregivers of patients with CUP and common cancer, respectively. The families of CUP patients scored significantly higher on all three burden subscales than those of common cancer patients (effect sizes: specialist access subscale, 0.3; uncertainty subscale, 0.66; and prolonged diagnosis subscale, 0.69; adjusted P < 0.01). Greater family burden was significantly associated with lower patient QOL and higher family depression. Burden was significantly associated with being a spouse, second opinion consultation, and diagnosis period of > 1 month.

CONCLUSION

The family caregivers of CUP patients experience poor specialist access, greater uncertainty, and a prolonged diagnosis. They should be cared for from the initial stages to establish access to specialists, obtain an early diagnosis, and reduce uncertainty.

Comprehensive evaluation on cancer of unknown primary site and how we managed it: A case report

Introduction and importance

Cancer of unknown primary site (CUP) is metastatic cancer without primary tumor found from comprehensive medical history, physical examination, and regular laboratory examination. Eighty percent of CUP include unfavorable groups with 3 to 6 months of median survival despite chemotherapy treatment.

Case presentation

A 52-year-old male was presented with a chief complaint of a recurrent lump in the neck and axilla. After comprehensive examinations over three years, the primary site of the metastatic tumor could not be found. Therefore, this patient was diagnosed with cancer of an unknown primary site.

Clinical discussion

In patient with CUP, more precise therapy can only begin when the exact form of cancer is identified. However, the delay in diagnosis would worsen the patient's condition, as treatment measures cannot be implemented.

Conclusion

Trimodal modalities including surgery, chemotherapy, and radiotherapy are suitable for CUP with squamous cell carcinoma proven in immunohistochemistry evaluation.

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Precise therapy for patients with CUP can only begin when the exact form of cancer is identified.

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Although PET/CT is suitable to assess the complete body state for CUP, other radiological and histopathology modalities are needed to confirm the diagnosis.

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Trimodal modalities including surgery, chemotherapy, and radiotherapy are required for CUP with squamous cell carcinoma.

Favorable Response to Olaparib in a Patient with Cancer of Unknown Primary Carrying a Germline BRCA1 R71K Mutation

The treatment options for cancer of unknown primary (CUP) are challenging due to the lack of knowledge about the primary sites, often resulting in a poor prognosis. The emerging next-generation sequencing (NGS) technique has provided a reliable approach to facilitate tumor primary site prediction and targetable gene alteration identification for CUP patients. In this report, we described a 63-year-old female patient who experienced recurrent CUP. NGS-based genetic profiling results revealed a pathogenic germline BRCA1 R71K mutation. Accordingly, the patient received the poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitor olaparib treatment and demonstrated a favorable response to this treatment. Our case suggests that NGS holds great promise for providing improved diagnosis and treatment options to patients with CUP, warranting further clinical investigation.

The cell of cancer origin provides the most reliable roadmap to its diagnosis, prognosis (biology) and therapy

Cancers arise from single transformed cells from virtually every organ of the body, divide in a relatively uncontrolled manner, and metastasize widely. A search for a "magic bullet" to precisely diagnose, characterize, and ultimately treat cancer has largely failed because cancer cells do not differ significantly from their organ-specific cells of origin. Instead of searching for genomic, epigenetic, transcriptional, and translational differences between cancers and their cells of origin, we should paradoxically focus on what cancer cells have in common with their untransformed cells of origin. This redirected search will lead to improved diagnostic and therapeutic strategies where therapeutic index considerations and drug-limiting toxicities can largely be circumvented. We cite three cancer examples that illustrate this paradigm-shifting strategy: pseudomyxoma peritonei (PP), metastasis of unknown origin (cancers of unknown primary) (MUO), and cancers that arise from potentially dispensable organs (CAD). In each of these examples, the cell of cancer origin still provides the most reliable road map to its diagnosis, prognosis (biology), and therapy.

Descriptive epidemiology of cancer of unknown primary in South Korea, 1999-2017

BACKGROUND

Cancers of unknown primary (CUPs) are tumors found after metastasizing from unidentified primary sites; these tumors generally have unknown treatment strategies, expected treatment results, and prognosis. We assessed the epidemiological characteristics of CUPs in Korea.

METHODS

We extracted records for 1999 through 2017 from the Korea Central Cancer Registry using the International Statistical Classification of Diseases and Related Health Problems (10th revision) codes for CUP as defined by the International Agency for Research on Cancer. Age-standardized rates and relative survival rates were calculated.

RESULTS

The CUPs constituted 2.1 % of the total number of cancer registrations in 1999, declining to 0.7 % in 2017. The incidence rate decreased for both sexes (5.35 to 2.20 for men, 3.15 to 1.77 for women). Patients aged 80 years and older had the highest incidence rate at 40.2, and 86.3 % of CUPs occurred in those 50 years of age or older. The cases of retroperitoneum and peritoneum sites increased over time. Cases diagnosed by microscopic methods and death certification only were 62.3 % and 7.9 %, respectively. The malignant neoplasm of the retroperitoneum and peritoneum and unknown primary site had the highest and lowest survival rates, respectively. The 5-year relative survival rate increased over time from 14.2 % (1999-2002) to 27.3 % (2013-2017).

CONCLUSIONS

Our analysis of data from the Korea Central Cancer Registry found decreasing rates of CUP, although with consistent disparities by patient age and sex. Advancements in diagnostic technology may be decreasing the number of CUP diagnoses. Expanding the amount of information recorded in the registry may further improve diagnostic accuracy.

A receptor-antibody hybrid hampering MET-driven metastatic spread

Background

The receptor encoded by the MET oncogene and its ligand Hepatocyte Growth Factor (HGF) are at the core of the invasive-metastatic behavior. In a number of instances genetic alterations result in ligand-independent onset of malignancy (MET addiction). More frequently, ligand stimulation of wild-type MET contributes to progression toward metastasis (MET expedience). Thus, while MET inhibitors alone are effective in the first case, combination therapy with ligand inhibitors is required in the second condition.

Methods

In this paper, we generated hybrid molecules gathering HGF and MET inhibitory properties. This has been achieved by ‘head-to-tail’ or ‘tail-to-head’ fusion of a single chain Fab derived from the DN30 MET antibody with a recombinant ‘ad-hoc’ engineered MET extracellular domain (decoyMET), encompassing the HGF binding site but lacking the DN30 epitope.

Results

The hybrid molecules correctly bind MET and HGF, inhibit HGF-induced MET downstream signaling, and quench HGF-driven biological responses, such as growth, motility and invasion, in cancer cells of different origin. Two metastatic models were generated in mice knocked-in by the human HGF gene: (i) orthotopic transplantation of pancreatic cancer cells; (ii) subcutaneous injection of primary cells derived from a cancer of unknown primary. Treatment with hybrid molecules strongly affects time of onset, number, and size of metastatic lesions.

Conclusion

These results provide a strategy to treat metastatic dissemination driven by the HGF/MET axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-020-01822-5.

The role of molecular profiling in the diagnosis and management of metastatic undifferentiated cancer of unknown primary✰: Molecular profiling of metastatic cancer of unknown primary

Cancer of unknown primary (CUP) refers to metastatic tumors for which the primary tumor of origin cannot be determined at the time of diagnosis, despite extensive clinicopathologic investigations. Molecular profiling is increasingly able to predict a probable primary tumor type for CUP when clinicopathologic workup is inconclusive. Numerous studies have explored the use of various molecular profiling techniques for identification of site/tissue of origin of CUP. These techniques include gene expression profiling utilizing microarray, reverse transcriptase polymerase chain reaction, RNA-sequencing, somatic gene mutation profiling with next-generation DNA sequencing, and epigenomics including DNA methylation profiling. Despite the generally poor prognosis of CUP, a minority of patients can expect to benefit from targeted therapy despite being agnostic to the tissue of origin. Studies have explored the use of various molecular profiling techniques to predict prognostic and therapeutic biomarkers, with the goal of improving outcome for patients with CUP. However, discordant results between non-randomized and randomized clinical trials in evaluating tumor-type specific therapies raise uncertainties of the benefits of molecularly-predicted tissue of origin-based treatment in routine clinical use. Nevertheless, the current overall trend is in favor of using molecular tools to refine the diagnosis and clinical management of patients with CUP. More large-cohort, randomized prospective studies are needed to assess and validate the utility and feasibility of molecular profiling to uncover potentially targetable genetic alterations. These efforts will also yield further biological insights into the biology and pathogenesis of CUP (Graphical Abstract).