Neurologic Clinical, Electrophysiologic, and Pathologic Characteristics of Primary vs Secondary Neurolymphomatosis

BACKGROUND AND OBJECTIVES

Neurolymphomatosis (NL) is characterized by lymphomatous infiltration of the peripheral nervous system presenting as the initial manifestation of a lymphoma (primary NL [PNL]) or in relapse of a known lymphoma (secondary NL [SNL]). This report details and compares the neurologic clinicopathologic characteristics of these 2 groups.

METHODS

This retrospective study was performed on patients diagnosed with pathologically confirmed NL in nerve between January 1, 1992, and June 31, 2020. Patient clinical characteristics, neurologic examination, imaging studies, EMG, and nerve biopsy data were collected, analyzed, and compared between PNL and SNL.

RESULTS

A total of 58 patients were identified (34 PNL and 24 SNL). Time from neurologic symptom onset to diagnosis was longer in PNL at 18.5 months compared with 5.5 months in SNL (p = 0.01). Neurologic symptoms were similar in both patient groups and included primarily sensory loss (98%), severe pain (76%), and asymmetric weakness (76%). A wide spectrum of EMG-confirmed different neuropathy patterns were observed, but patients with SNL had increased numbers of mononeuropathies (n = 8) compared with PNL (n = 1, p = 0.01). MRI studies detected NL more frequently (86%) compared with fluorodeoxyglucose (FDG)-PET CT imaging studies (60%) (p = 0.007). Nerve biopsies revealed B-cell lymphoma (PNL n = 32, SNL n = 22), followed by T-cell lymphoma (PNL n = 2, SNL n = 2), with increased demyelination in both groups and increased axonal degeneration (p = 0.01) and multifocal myelinated fiber loss (p = 0.04) significant in SNL vs PNL. Identifying SNL resulted in patient treatment modifications but a worse prognosis compared with PNL (p = 0.025).

DISCUSSION

While PNL and SNL are both primarily painful and asymmetric neuropathies with axonal and demyelinating features on EMG and nerve biopsy, SNL presents somewhat differently than PNL with fulminant, asymmetric often mononeuropathies better detected on MRI than FDG-PET/CT. The focal pattern of SNL is likely a result of residual cancer cells that evaded initial chemotherapy, which does not cross the blood-nerve barrier, and these cells can later recur and result in fulminant disease. Although still resulting in a poorer prognosis, identifying SNL is important because this changed treatment and management in every SNL case.

PET2 response associated with survival in newly diagnosed diffuse large B-cell lymphoma: results of two independent prospective cohorts

Studies evaluating Positron Emission Tomography scan after 2 cycles of chemotherapy (PET2) in newly diagnosed diffuse large B cell lymphoma (DLBCL) are heterogeneous in patient characteristics, treatments and have conflicting results. Here we report association of PET2 with outcomes in two large independent prospective cohorts of newly diagnosed DLBCL pts treated with two RCHOP-based regimens. The discovery cohort consisted of pts enrolled in single arm phase 2 MC078E study of lenalidomide with RCHOP (R2CHOP). The validation cohort consisted of RCHOP-treated pts from the Molecular Epidemiology Resource (MER) cohort. Pts who received 3-6 cycles of therapy and had PET2 were included in the study. Patients who progressed on PET2 were excluded. Revised response criteria 2007 were used to define PET2 response PET2 positive (PET2 + ) pts had inferior EFS [24-month EFS 45.5% vs 87.9%, HR 4.0, CI₉₅ (2.1-7.9), p < 0.0001) with a trend towards lower OS [24-months OS 77% vs 94.8%, HR 2.0, CI₉₅ (0.9-4.8), P = 0.1] than PET2 negative (PET2-) pts in MC078E cohort. PET2 + pts had an inferior EFS (24 month EFS 48.7% vs 81.6%, HR 2.9, CI₉₅ 2.0-4.2, p < 0.0001) and OS (24-month OS 68.6% vs 88.1%, HR 2.3, CI₉₅: 1.5-3.5, p < 0.0001) in the MER cohort. These results were consistent regardless of age, sex and in the subgroup of advanced stage and high-risk international prognostic index (IPI). For MER, PET2 + pts also had higher odds of positive end of treatment PET (OR: 17.3 (CI₉₅ 7.9-37.7), p < 0.001). PET2 is an early predictor DLBCL pts at high risk of progression and death in two independent prospective cohorts. PET2-guided risk-adapted strategies may improve outcomes, and should be explored in clinical trials.

Clinicopathologic Characteristics, Treatment, and Outcomes of Post-transplant Lymphoproliferative Disorders: A Single-institution Experience Using 2017 WHO Diagnostic Criteria

The World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues (WHO 2017) included updated criteria for diagnosis and classification of post-transplant lymphoproliferative disorders (PTLDs). This study evaluated the clinicopathologic spectrum using WHO 2017 criteria and adult PTLD patients' outcomes over 30 years between 1987 and 2017 at Mayo Clinic (Rochester, MN). Patients were retrospectively reviewed for clinical features, outcomes, and diagnostic pathology material and classified based on WHO 2017 criteria. A total of 227 patients were diagnosed with PTLD, with a median time from transplant to PTLD of 45 months. PTLD occurred >1 year after transplant in 149 (66%) patients. Monomorphic PTLD was the most common subtype (173, 76%), with diffuse large B cell lymphoma as the commonest morphology (n = 137). Epstein-Barr virus was positive in 61% of total cases and 90% of PTLD that developed within 1 year from transplant. The median event-free survival (EFS) and overall survival for the entire cohort were 21 months (95% confidence interval [CI]: 9-35) and 82 months (95% CI: 39-115), respectively. The EFS or overall survival was not impacted by Epstein-Barr virus status but differed based on WHO subtypes and year of diagnosis. Management changed over time with increased use of rituximab or chemotherapy + immunosuppression reduction as initial therapy. When compared to the matched general population and de novo diffuse large B cell lymphoma, patients not achieving EFS 24 status (no progression/treatment or death within 24 mo of diagnosis) had a worse standardized mortality ratio 16.75 (95% CI: 13.91-20) versus SMR 1.72 (95% CI: 1.26-2.28) in those who achieved EFS24. Cause of death was mostly attributed to non-lymphoma-related causes in those achieving EFS 24.

Patterns of therapy initiation during the first decade for patients with follicular lymphoma who were observed at diagnosis in the rituximab era

Immediate treatment for asymptomatic, low-tumor burden follicular lymphoma (FL) has not shown an overall survival benefit over "watch and wait" (W/W) strategy. We estimated incidence of treatment initiation at specific time points and assessed its association with the presence of any criteria such as GELF, BNLI, GITMO at diagnosis. FL patients managed by W/W strategy were identified from the Molecular Epidemiology Resource (MER) of the University of Iowa/Mayo Clinic Lymphoma SPORE between 2002 and 2015. Cumulative incidence estimates of treatment initiation were calculated using transformation (as the first event) and death as competing risks. 401 FL patients were identified on W/W strategy. At a median follow-up of 8 years, 256 (64%) initiated treatment. For patients on the W/W strategy for 5 years, the likelihood of treatment initiation in the next 5 years was 12% compared to 43% at diagnosis unlike transformation rates which remained steady. Patients with any of popular treatment criteria at diagnosis did not have increased therapy initiation rates (44% vs. 42%) during the first 5 years or lymphoma-related death rates at 10 years (6% vs. 7%). Identifying biological differences in patients with early vs. late or no progression is a critical next step in understanding outcomes in W/W patients.

Addition of Lenalidomide to R-CHOP Improves Outcomes in Newly Diagnosed Diffuse Large B-Cell Lymphoma in a Randomized Phase II US Intergroup Study ECOG-ACRIN E1412

PURPOSE

Lenalidomide combined with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) (R2CHOP) in untreated diffuse large B-cell lymphoma (DLBCL) has shown promising activity, particularly in the activated B-cell-like (ABC) subtype. Eastern Cooperative Oncology Group (ECOG)-ACRIN trial E1412 was a randomized phase II study comparing R2CHOP versus R-CHOP in untreated DLBCL.

PATIENTS AND METHODS

Patients with newly diagnosed DLBCL, stage II bulky-IV disease, International Prognostic Index (IPI) ≥ 2, and ECOG performance status ≤ 2 were eligible and randomly assigned 1:1 to R2CHOP versus R-CHOP for six cycles. Tumors were analyzed using the NanoString Lymph2Cx for cell of origin. The primary end point was progression-free survival (PFS) in all patients with the co-primary end point of PFS in ABC-DLBCL. Secondary end points included overall response rate (ORR), complete response (CR) rate, and overall survival (OS).

RESULTS

Three hundred forty-nine patients were enrolled; 280 patients (145 R2CHOP and 135 R-CHOP) were evaluable: 94 were ABC-DLBCL, 122 germinal center B-cell-like-DLBCL, 18 unclassifiable, and 46 unknowns. Baseline characteristics were well-balanced between arms, and the median age was 66 (range, 24-92); 70% of patients had stage IV disease; 34%, 43%, and 24% had IPI 2, 3, and 4 or 5, respectively. Myelosuppression was more common in the R2CHOP arm. The ORR and CR rate were 92% and 68% in R-CHOP and 97% (P = .06) and 73% (P = .43) in the R2CHOP arm, respectively. The median follow-up was 3.0 years; R2CHOP was associated with a 34% reduction in risk of progression or death versus R-CHOP (hazard ratio [HR], 0.66 95% CI, 0.43 to 1.01) and 3-year PFS of 73% versus 61%, one-sided P = .03, and an improvement in OS (83% and 75% at 3 years; HR, 0.67; one-sided P = .05). The PFS HR for R2CHOP was 0.67 for ABC-DLBCL, one-sided P = .1.

CONCLUSION

In this signal-seeking study, the addition of lenalidomide to R-CHOP (R2CHOP) improved outcomes in newly diagnosed DLBCL including patients with ABC-DLBCL.

Aspirin and other nonsteroidal anti-inflammatory drugs, statins and risk of non-Hodgkin lymphoma

Non-steroidal anti-inflammatory drugs (NSAIDs) and statin drugs may protect against the development of non-Hodgkin lymphoma (NHL), but data are limited, particularly for NHL subtypes. Furthermore, some in vitro, animal and epidemiologic data suggest there may be a synergistic effect of these two agents, but there has been no test of this hypothesis in NHL. We evaluated the self-reported use of NSAIDs and statins in a clinic-based study of 1703 NHL patients and 2199 frequency-matched controls. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for potential confounding variables. We observed an inverse association of regular use of low-dose aspirin with risk of NHL (OR = 0.82; 95% CI 0.70-0.96) that was stronger with longer duration of use (P < .01). There were no associations for use of regular or extra-strength aspirin, ibuprofen, other NSAIDs, statins or other cholesterol-lowering drugs with NHL risk, while an inverse association with COX-2 inhibitors was equivocal. There was also no interaction of low-dose aspirin and statins on NHL risk. Inverse associations of similar magnitude to all NHL were observed for regular use of low-dose aspirin with diffuse large B-cell, follicular, marginal zone and all other lymphomas, although not all associations were statistically significant. In conclusion, low-dose aspirin but not regular/extra strength aspirin, other NSAIDs or statin use was associated with lower risk of NHL. Beyond the potential for the primary prevention of NHL, these data also point to a role of anti-platelet or other effects of low-dose aspirin in lymphomagenesis that warrant follow-up.

Targeting of inflammatory pathways with R2CHOP in high-risk DLBCL

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma, and front line therapies have not improved overall outcomes since the advent of immunochemotherapy. By pairing DNA and gene expression data with clinical response data, we identified a high-risk subset of non-GCB DLBCL patients characterized by genomic alterations and expression signatures capable of sustaining an inflammatory environment. These mutational alterations (PIM1, SPEN, and MYD88 [L265P]) and expression signatures (NF-κB, IRF4, and JAK-STAT engagement) were associated with proliferative signaling, and were found to be enriched in patients treated with RCHOP that experienced unfavorable outcomes. However, patients with these high-risk mutations had more favorable outcomes when the immunomodulatory agent lenalidomide was added to RCHOP (R2CHOP). We are the first to report the genomic validation of a high-risk phenotype with a preferential response towards R2CHOP therapy in non-GCB DLBCL patients. These conclusions could be translated to a clinical setting to identify the ~38% of non-GCB patients that could be considered high-risk, and would benefit from alternative therapies to standard RCHOP based on personalized genomic data.

Analysis and impact of a multidisciplinary lymphoma virtual tumor board

The aim is to prospectively evaluate the impact of a multidisciplinary lymphoma virtual tumor board. The utility of multi-site interactive lymphoma-specific tumor boards has not been reported. The Mayo Clinic Lymphoma Tumor Board is a component of the International Mayo Clinic Care Network (MCCN). The format includes the clinical case presentation, presentation of radiology and hematopathology findings by the appropriate subspecialist, proposed treatment options, review of the literature pertinent to the case, pharmacy contributions, and discussion followed by recommendations. Three hundred and nine consecutive highly selected real-time cases with a diagnosis of lymphoma were presented at the Mayo Clinic Lymphoma Tumor Board from January 2014 to June 2018 and decisions were prospectively tracked to assess its impact on the treatment decisions. A total of 309 cases were prospectively evaluated. One hundred and forty (45.3%) cases had some changes made or recommended. The total changes suggested were 179, as some cases had more than one recommendation. There were 93 (30%) clinical management recommendations, 45 (14.6%) additional testing recommendations, 29 (9.4%) pathology changes, and 6 (1.9%) radiology changes. In an electronic evaluation process, 93% of the responders reported an improvement in knowledge and competence, and 100% recommended no change in format of the board. A multidisciplinary lymphoma tumor board approach was found to have a meaningful impact on lymphoma patients while enhancing interdisciplinary interactions and education for multiple levels of the clinical care team.

Fluorodeoxyglucose-Positron Emission Tomography Predicts Bone Marrow Involvement in the Staging of Follicular Lymphoma

BACKGROUND

Standard bone marrow biopsy (BMB) and bone involvement with follicular lymphoma (FL) on positron emission tomography (PET)/computed tomography (CT) both predict early clinical failure in FL. The key clinical question is whether PET/CT findings can obviate the need for BMB. The goal of this study was to determine the value of PET/CT in determining bone involvement in FL, using posterior iliac crest BMB as the gold standard.

MATERIALS AND METHODS

A total of 548 patients with newly diagnosed grade 1-3A FL were included. The presence, pattern, and location of bone involvement, spleen involvement, and standardized uptake values (SUVs) in the L3 vertebral body were recorded for all patients and compared with the BMB report.

RESULTS

Excluding patients with focal bone lesions on PET/CT, the sensitivity and specificity of PET/CT in detecting bone or marrow involvement, compared with BMB, were 53% and 88%, respectively. The sensitivity and specificity of spleen involvement on PET/CT in predicting a positive BMB were 55% and 86%, respectively. An L3 SUVmax of less than 2.0 resulted in a negative predictive value (NPV) of 96% for marrow involvement on BMB; an L3 SUVmean below 1.4 resulted in an NPV of 100%.

CONCLUSION

In newly diagnosed FL, PET/CT-detected bone and splenic involvement is highly specific for a positive BMB, and very low SUV values (<2.0 SUVmax and < 1.4 SUVmean ) in the lumbar spine have a high NPV for a negative BMB. Routine BMB may be obviated in these patients. BMB remains necessary to definitively exclude bone marrow involvement in a large majority of patients with a negative PET.

IMPLICATIONS FOR PRACTICE

Predicting early clinical failure in follicular lymphoma (FL) is important but difficult. Bone marrow involvement by FL is associated with early clinical failure, and determining this involvement is a key component of the initial staging. This study highlights that in certain patients, positron emission tomography/computed tomography is sufficient in determining bone or marrow involvement, without the need for a confirmatory bone marrow biopsy (BMB). An algorithm is provided based on these findings to help clinicians determine which patients would benefit from BMB and when it can be avoided.

Association between bone involvement on PET/CT and event free survival (EFS) in follicular lymphoma (FL) grade 3b

e20068

Background: FL grade 3B (FL3B) is an aggressive subtype of FL with a distinct morphologic, cytogenetic and immunohistochemical profile that is associated with higher mortality compared to other subtypes of FL. FL3B is a rare disease, and data regarding its prognostication beyond grading is lacking. Recent data suggests that spleen and extranodal (EN) involvement on PET/CT predict early clinical failure in FL grades 1-3A[1]. We aimed to determine the incidence of spleen and EN involvement on PET/CT in FL3B, and whether these can predict EFS. Methods: Patients with untreated FL3B diagnosed between 2003-2016, with available pre-treatment PET/CT, were identified using the Mayo Clinic Lymphoma Database and the University of Iowa/Mayo Clinic Lymphoma SPORE database. 27 patients were included in this analysis. All but two patients received treatment with immunochemotherapy. Associations with outcomes were assessed using EFS, defined as disease progression, relapse, transformation, or death. Results: 11/27 (40.7%) of patients had EN involvement on PET/CT. The most common EN site was bone, in 8/27 (29.5%) of patients. Soft tissue involvement was present in 4/27 (14.8%) of patients. Liver, brain, and endometrial involvement were each noted once. 11/27 (40.7%) of patients had spleen involvement on PET/CT. Presence of bone involvement as detected on PET/CT was associated with lower EFS (p = 0.02). EN involvement was associated with a trend toward a lower EFS but statistical significance was not reached likely secondary to low numbers in this cohort. Results in the table are compared to results obtained from our analysis in patients with FL grade 1-3A[1]. Conclusions: Bone involvement on pre-treatment PET/CT in FL3B was associated with early clinical failure in this small cohort of 27 patients. EN involvement at diagnosis may also be associated with poorer outcomes. These findings are similar to our analysis of a large (n = 613) cohort of patients with FL grade 1-3A. These findings may aid in the prognostication of patients with newly diagnosed FL3B, to guide therapy in select higher risk patients. [Table: see text]

Phase I/II study of R-ICE (rituximab-ifosfamide-carboplatin-etoposide) with lenalidomide (R2-ICE) in patients with first-relapse/primary refractory diffuse large B-cell lymphoma (DLBCL) in academic and community cancer research united (ACCRU) network

TPS8073

Background: Response rates to salvage immunochemotherapy in patients with DLBCL relapsing after or refractory (R/R DLBCL) to front line therapy remain unsatisfactory. Lenalidomide (Len) has significant single agent activity in relapsed/refractory DLBCL. The addition of lenalidomide (Len) days 1-7 to rituximab plus ifosfamide-carboplatin-etoposide (RICE) was shown to be feasible with promising efficacy in phase 1b study (Feldman T, et al. BJH, 2014). We developed phase I/II study to evaluate the safety and efficacy of the addition of Len (extended to 14 day schedule) to RICE (R2-ICE) for R/R-DLBCL patients who are candidates for stem cell transplant. Methods: The phase I portion was designed to determine the maximally tolerated dose Len in combination with RICE using the standard cohort 3+3 design. The escalation dose levels were 15 mg and 20 mg daily x 14 days. Prophylactic aspirin and growth factor support is mandatory. After 2 cycles of therapy response is evaluated with a PET/CT scan; the responding patients are eligible for 1-2 additional cycles of R2ICE as a bridging before HDC/SCT. The estimated overall response rate for two cycles of R-ICE in R/R DLBCL to RCHOP was estimated to be approximate 45%. We hypothesize that the addition of lenalidomide in the relapse setting could increase the overall response rate by approximately 20%. The one-stage design with an interim analysis being utilized in phase 2 requires 45 evaluable patients (one sided alpha = 0.09, power 90%). For Phase I, all types of B-cell lymphomas were eligible. For phase II portion only DLBCL patients are eligible per central pathology review. Other eligibility criteria include: received one line of previous anti-lymphoma therapy, ≥ 2 weeks from completion of prior anti-lymphoma therapy, candidate for HDC and SCT, adequate organ (creatinine clearance ≥ 60ml/min by Cockcroft-, total bilirubin ≤ 2 × ULN) and bone marrow function (ANC) ≥1500/mm3; platelet count ≥75,000/mm3). The use of steroids and/or rituximab up to 1 week prior to registration for management of symptoms is allowed. 9 patients cleared phase 1 without DLT and dose of 20 mg days 1 -14 was recommend for phase 2 part (RP2D) of the study. The phase 2 study passed interim futility analysis and accrual continues. Correlatives include cell of origin by Nanostring, Myc/bcl2 expression and by FISH and minimal residual disease. PET scans are centrally reviewed including metabolic tumor volume. Clinical trial information: NCT02628405 .

HISTOLOGIC FINDINGS IN VITREORETINAL LYMPHOMA: Learning From Enucleation Specimens

PURPOSE

We aimed to describe the clinical and histologic findings in a few enucleation cases with intraocular lymphoma.

METHODS

Retrospective review of pathology files from a 22-year period identified cases with intraocular lymphoma among all enucleation specimens. Patient demographics, clinical findings, laboratory results, radiographic studies, and indication for enucleation were abstracted from electronic health records; slides were reviewed.

RESULTS

Four patients (three women and one man; age range, sixth through eighth decades of life) underwent enucleation with a final diagnosis of intraocular lymphoma. Two patients with primary vitreoretinal large B-cell lymphomas had been treated for refractory uveitis. Specimens showed retinal and subretinal infiltrates by atypical large B-lymphocytes and rare neoplastic cells in the vitreous. The remaining two patients had systemic lymphoproliferative disorders. One patient had chronic lymphocytic leukemia and floaters in his eye; vitreoretinal lymphoma developed, consistent with intraocular Richter transformation. The other had diffuse large B-cell lymphoma in remission; however, blurred vision developed, she was treated for panuveitis without improvement, and was later found to have ocular involvement by diffuse large B-cell lymphoma.

CONCLUSION

Our series details the unusual circumstances when an eye is removed for intraocular lymphoma. Different patterns of ocular tissue involvement were observed when we compared primary and secondary lymphomas.

Desmoplastic Infantile Ganglioglioma: A MAPK Pathway-Driven and Microglia/Macrophage-Rich Neuroepithelial Tumor

MAPK pathway activation has been recurrently observed in desmoplastic infantile ganglioglioma/astrocytoma (DIG/DIA) with reported disproportionally low mutation allele frequencies relative to the apparent high tumor content, suggesting that MAPK pathway alterations may be subclonal. We sought to expand the number of molecularly profiled cases and investigate if tumor cell composition could account for the observed low mutation allele frequencies. Molecular (targeted neuro-oncology next-generation sequencing/RNA sequencing and OncoScan microarray) and immunohistochemical (CD68-PGM1/CD163/CD14/CD11c/lysozyme/CD3/CD20/CD34/PD-L1) studies were performed in 7 DIG. Activating MAPK pathway alterations were identified in 4 (57%) cases: 3 had a BRAF mutation (V600E/V600D/V600_W604delinsDQTDG, at 8%–27% variant allele frequency) and 1 showed a TPM3-NTRK1 fusion. Copy number changes were infrequent and nonrecurrent. All tumors had at least 30% of cells morphologically and immunophenotypically consistent with microglial/macrophage lineage. Two subtotally resected tumors regrew; 1 was re-excised and received adjuvant treatment (chemotherapy/targeted therapy), with clinical response to targeted therapy only. Even with residual tumor, all patients are alive (median follow-up, 83 months; 19–139). This study further supports DIG as another MAPK pathway-driven neuroepithelial tumor, thus expanding potential treatment options for tumors not amenable to surgical cure, and suggests that DIG is a microglia/macrophage-rich neuroepithelial tumor with frequent low driver mutation allele frequencies.

Combined Tumors in Hematolymphoid Neoplasms: Case Series of Histiocytic and Langerhans Cell Sarcomas Arising From Low-Grade B-Cell Lymphoma

We report an index case of histiocytic sarcoma arising in a 70-year-old patient with long-standing chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). The patient presented in 2017 with painful, enlarging swelling of the left neck. He had remote history of cutaneous squamous cell carcinoma with no sign of recurrence, and his CLL/SLL was thought to be in remission. Computed tomography showed mild splenomegaly and multifocal lymphadenopathy including a 3-cm left neck mass. Biopsy of the left neck mass showed CLL/SLL with associated histiocytic sarcoma. Flow cytometry demonstrated a B cell neoplasm with CLL/SLL phenotype. Despite radiation therapy, he expired 3 months after presentation. Two similar cases (CLL/SLL and histiocytic sarcoma, follicular lymphoma and Langerhans cell sarcoma) from another institution are also illustrated. The pathological features of combined tumors in lymphoid neoplasms, a general framework to the work-up to determine interrelatedness of tumor components, and the clinical relevance are discussed.